diff --git a/src/DSP/AnalogFilter.cpp b/src/DSP/AnalogFilter.cpp
index 58f46a21..b25f1f6c 100644
--- a/src/DSP/AnalogFilter.cpp
+++ b/src/DSP/AnalogFilter.cpp
@@ -391,7 +391,11 @@ void AnalogFilter::filterout(float *smp)
 
     if(needsinterpolation) {
         //Merge Filter at old coeff with new coeff
+#ifdef _MSC_VER
+        const auto ismp = static_cast<float*>(_alloca(buffersize * sizeof(float)));
+#else
         float ismp[buffersize];
+#endif
         memcpy(ismp, smp, bufferbytes);
 
         for(int i = 0; i < stages + 1; ++i)
diff --git a/src/DSP/FormantFilter.cpp b/src/DSP/FormantFilter.cpp
index 36db5f6d..26761901 100644
--- a/src/DSP/FormantFilter.cpp
+++ b/src/DSP/FormantFilter.cpp
@@ -204,13 +204,18 @@ void FormantFilter::setfreq_and_q(float frequency, float q_)
 
 void FormantFilter::filterout(float *smp)
 {
+#ifdef _MSC_VER
+    const auto inbuffer = static_cast<float*>(_alloca(buffersize * sizeof(float)));
+    const auto tmpbuf = static_cast<float*>(_alloca(buffersize * sizeof(float)));
+#else
     float inbuffer[buffersize];
+    float tmpbuf[buffersize];
+#endif
 
     memcpy(inbuffer, smp, bufferbytes);
     memset(smp, 0, bufferbytes);
 
     for(int j = 0; j < numformants; ++j) {
-        float tmpbuf[buffersize];
         for(int i = 0; i < buffersize; ++i)
             tmpbuf[i] = inbuffer[i] * outgain;
         formant[j]->filterout(tmpbuf);
diff --git a/src/DSP/SVFilter.cpp b/src/DSP/SVFilter.cpp
index 5e27c39c..49fed553 100644
--- a/src/DSP/SVFilter.cpp
+++ b/src/DSP/SVFilter.cpp
@@ -165,7 +165,11 @@ void SVFilter::filterout(float *smp)
         singlefilterout(smp, st[i], par);
 
     if(needsinterpolation) {
+#ifdef _MSC_VER
+        const auto ismp = static_cast<float*>(_alloca(buffersize * sizeof(float)));
+#else
         float ismp[buffersize];
+#endif
         memcpy(ismp, smp, bufferbytes);
 
         for(int i = 0; i < stages + 1; ++i)
diff --git a/src/Effects/EffectMgr.cpp b/src/Effects/EffectMgr.cpp
index 08d4f1d8..7d9fdc60 100644
--- a/src/Effects/EffectMgr.cpp
+++ b/src/Effects/EffectMgr.cpp
@@ -34,7 +34,7 @@
 #include <iostream>
 using namespace std;
 
-EffectMgr::EffectMgr(const bool insertion_, pthread_mutex_t *mutex_)
+EffectMgr::EffectMgr(const bool insertion_, std::mutex *mutex_)
     :insertion(insertion_),
       efxoutl(new float[synth->buffersize]),
       efxoutr(new float[synth->buffersize]),
@@ -142,9 +142,9 @@ void EffectMgr::changepreset_nolock(unsigned char npreset)
 //Change the preset of the current effect(with thread locking)
 void EffectMgr::changepreset(unsigned char npreset)
 {
-    pthread_mutex_lock(mutex);
+    mutex->lock();
     changepreset_nolock(npreset);
-    pthread_mutex_unlock(mutex);
+    mutex->unlock();
 }
 
 
@@ -159,9 +159,9 @@ void EffectMgr::seteffectpar_nolock(int npar, unsigned char value)
 // Change a parameter of the current effect (with thread locking)
 void EffectMgr::seteffectpar(int npar, unsigned char value)
 {
-    pthread_mutex_lock(mutex);
+    mutex->lock();
     seteffectpar_nolock(npar, value);
-    pthread_mutex_unlock(mutex);
+    mutex->unlock();
 }
 
 //Get a parameter of the current effect
diff --git a/src/Effects/EffectMgr.h b/src/Effects/EffectMgr.h
index 256a8d81..71e2548b 100644
--- a/src/Effects/EffectMgr.h
+++ b/src/Effects/EffectMgr.h
@@ -22,7 +22,7 @@
 #ifndef EFFECTMGR_H
 #define EFFECTMGR_H
 
-#include <pthread.h>
+#include "ThreadShims.h"
 
 #include "Alienwah.h"
 #include "Phaser.h"
@@ -43,7 +43,7 @@ class XMLwrapper;
 class EffectMgr:public Presets
 {
     public:
-        EffectMgr(const bool insertion_, pthread_mutex_t *mutex_);
+        EffectMgr(const bool insertion_, std::mutex *mutex_);
         ~EffectMgr();
 
         void add2XML(XMLwrapper *xml);
@@ -79,7 +79,7 @@ class EffectMgr:public Presets
     private:
         int     nefx;
         Effect *efx;
-        pthread_mutex_t *mutex;
+        std::mutex *mutex;
         bool dryonly;
 };
 
diff --git a/src/Effects/Reverb.cpp b/src/Effects/Reverb.cpp
index 74961b2f..b3f679e4 100644
--- a/src/Effects/Reverb.cpp
+++ b/src/Effects/Reverb.cpp
@@ -144,7 +144,11 @@ void Reverb::out(const Stereo<float *> &smp)
     if(!Pvolume && insertion)
         return;
 
+#ifdef _MSC_VER
+    const auto inputbuf = static_cast<float*>(_alloca(buffersize * sizeof(float)));
+#else
     float inputbuf[buffersize];
+#endif
     for(int i = 0; i < buffersize; ++i)
         inputbuf[i] = (smp.l[i] + smp.r[i]) / 2.0f;
 
diff --git a/src/Misc/Bank.cpp b/src/Misc/Bank.cpp
index 3d74629b..9e42e574 100644
--- a/src/Misc/Bank.cpp
+++ b/src/Misc/Bank.cpp
@@ -31,10 +31,15 @@
 #include <algorithm>
 #include <iostream>
 
+#ifdef WIN32
+#include <wchar.h>
+#include "IoHelper.h"
+#else
 #include <sys/types.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <errno.h>
+#endif
 
 #include "Config.h"
 #include "Util.h"
@@ -260,14 +265,14 @@ int Bank::newbank(string newbankdirname)
 
     // FIXME: Zyn should automatically handle creation of parent directory
 #ifdef WIN32
-    if(mkdir(bankdir.c_str()) < 0) return -1;
+    if(_wmkdir(lmms::toWString(bankdir).c_str()) < 0) return -1;
 #else
     if(mkdir(bankdir.c_str(), S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH)) return -1;
 #endif
 
     bankdir += newbankdirname;
 #ifdef WIN32
-    if(mkdir(bankdir.c_str()) < 0)
+    if(_wmkdir(lmms::toWString(bankdir).c_str()) < 0)
 #else
     if(mkdir(bankdir.c_str(), S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH) < 0)
 #endif
diff --git a/src/Misc/Master.cpp b/src/Misc/Master.cpp
index c4b8947b..331ab911 100644
--- a/src/Misc/Master.cpp
+++ b/src/Misc/Master.cpp
@@ -36,8 +36,6 @@
 #include <algorithm>
 #include <cmath>
 
-#include <unistd.h>
-
 using namespace std;
 
 vuData::vuData(void)
@@ -55,8 +53,6 @@ Master::Master()
     bufl = new float[synth->buffersize];
     bufr = new float[synth->buffersize];
 
-    pthread_mutex_init(&mutex, NULL);
-    pthread_mutex_init(&vumutex, NULL);
     fft = new FFTwrapper(synth->oscilsize);
 
     shutup = 0;
@@ -116,11 +112,11 @@ bool Master::mutexLock(lockset request)
 {
     switch(request) {
         case MUTEX_TRYLOCK:
-            return !pthread_mutex_trylock(&mutex);
+            return mutex.try_lock();
         case MUTEX_LOCK:
-            return !pthread_mutex_lock(&mutex);
+            mutex.lock(); return true;
         case MUTEX_UNLOCK:
-            return !pthread_mutex_unlock(&mutex);
+            mutex.unlock(); return true;
     }
     return false;
 }
@@ -245,9 +241,9 @@ void Master::setProgram(char chan, unsigned int pgm)
             //Hack to get pad note parameters to update
             //this is not real time safe and makes assumptions about the calling
             //convention of this function...
-            pthread_mutex_unlock(&mutex);
+            mutex.unlock();
             part[npart]->applyparameters();
-            pthread_mutex_lock(&mutex);
+            mutex.lock();
         }
 }
 
@@ -336,9 +332,9 @@ void Master::AudioOut(float *outl, float *outr)
 
     //Compute part samples and store them part[npart]->partoutl,partoutr
     for(int npart = 0; npart < NUM_MIDI_PARTS; ++npart) {
-        if(part[npart]->Penabled != 0 && !pthread_mutex_trylock(&part[npart]->load_mutex)) {
+        if(part[npart]->Penabled != 0 && part[npart]->load_mutex.try_lock()) {
             part[npart]->ComputePartSmps();
-            pthread_mutex_unlock(&part[npart]->load_mutex);
+            part[npart]->load_mutex.unlock();
         }
     }
 
@@ -394,8 +390,13 @@ void Master::AudioOut(float *outl, float *outr)
         if(sysefx[nefx]->geteffect() == 0)
             continue;  //the effect is disabled
 
+#ifdef _MSC_VER
+        const auto tmpmixl = static_cast<float*>(_alloca(synth->buffersize * sizeof(float)));
+        const auto tmpmixr = static_cast<float*>(_alloca(synth->buffersize * sizeof(float)));
+#else
         float tmpmixl[synth->buffersize];
         float tmpmixr[synth->buffersize];
+#endif
         //Clean up the samples used by the system effects
         memset(tmpmixl, 0, synth->bufferbytes);
         memset(tmpmixr, 0, synth->bufferbytes);
@@ -458,9 +459,9 @@ void Master::AudioOut(float *outl, float *outr)
         outr[i] *= volume;
     }
 
-    if(!pthread_mutex_trylock(&vumutex)) {
+    if(vumutex.try_lock()) {
         vuUpdate(outl, outr);
-        pthread_mutex_unlock(&vumutex);
+        vumutex.unlock();
     }
 
     //Shutup if it is asked (with fade-out)
@@ -530,9 +531,6 @@ Master::~Master()
         delete sysefx[nefx];
 
     delete fft;
-
-    pthread_mutex_destroy(&mutex);
-    pthread_mutex_destroy(&vumutex);
 }
 
 
@@ -588,21 +586,21 @@ void Master::ShutUp()
  */
 void Master::vuresetpeaks()
 {
-    pthread_mutex_lock(&vumutex);
+    vumutex.lock();
     vu.outpeakl    = 1e-9;
     vu.outpeakr    = 1e-9;
     vu.maxoutpeakl = 1e-9;
     vu.maxoutpeakr = 1e-9;
     vu.clipped     = 0;
-    pthread_mutex_unlock(&vumutex);
+    vumutex.unlock();
 }
 
 vuData Master::getVuData()
 {
     vuData tmp;
-    pthread_mutex_lock(&vumutex);
+    vumutex.lock();
     tmp = vu;
-    pthread_mutex_unlock(&vumutex);
+    vumutex.unlock();
     return tmp;
 }
 
@@ -673,9 +671,9 @@ int Master::getalldata(char **data)
 
     xml->beginbranch("MASTER");
 
-    pthread_mutex_lock(&mutex);
+    mutex.lock();
     add2XML(xml);
-    pthread_mutex_unlock(&mutex);
+    mutex.unlock();
 
     xml->endbranch();
 
@@ -695,9 +693,9 @@ void Master::putalldata(char *data, int /*size*/)
     if(xml->enterbranch("MASTER") == 0)
         return;
 
-    pthread_mutex_lock(&mutex);
+    mutex.lock();
     getfromXML(xml);
-    pthread_mutex_unlock(&mutex);
+    mutex.unlock();
 
     xml->exitbranch();
 
diff --git a/src/Misc/Master.h b/src/Misc/Master.h
index 2238d759..de37e484 100644
--- a/src/Misc/Master.h
+++ b/src/Misc/Master.h
@@ -23,7 +23,7 @@
 
 #ifndef MASTER_H
 #define MASTER_H
-#include <pthread.h>
+#include "ThreadShims.h"
 
 #include "../globals.h"
 #include "Microtonal.h"
@@ -162,8 +162,8 @@ class Master
         Bank       bank;
 
         class FFTwrapper * fft;
-        pthread_mutex_t mutex;
-        pthread_mutex_t vumutex;
+        std::mutex mutex;
+        std::mutex vumutex;
 
 
     private:
diff --git a/src/Misc/Part.cpp b/src/Misc/Part.cpp
index 144cec9f..fc999b71 100644
--- a/src/Misc/Part.cpp
+++ b/src/Misc/Part.cpp
@@ -36,12 +36,11 @@
 #include <stdio.h>
 #include <string.h>
 
-Part::Part(Microtonal *microtonal_, FFTwrapper *fft_, pthread_mutex_t *mutex_)
+Part::Part(Microtonal *microtonal_, FFTwrapper *fft_, std::mutex *mutex_)
 {
     microtonal = microtonal_;
     fft      = fft_;
     mutex    = mutex_;
-    pthread_mutex_init(&load_mutex, NULL);
     partoutl = new float [synth->buffersize];
     partoutr = new float [synth->buffersize];
 
@@ -232,7 +231,7 @@ void Part::NoteOn(unsigned char note,
     }
     else
     // Poly mode is On so just make sure the list is empty.
-    if(not monomemnotes.empty())
+    if(!monomemnotes.empty())
         monomemnotes.clear();
 
     lastnote = note;
@@ -254,7 +253,7 @@ void Part::NoteOn(unsigned char note,
         else {
             // Legato mode is on and applicable.
             legatomodevalid = true;
-            if((not ismonofirstnote) && (lastlegatomodevalid)) {
+            if((!ismonofirstnote) && (lastlegatomodevalid)) {
                 // At least one other key is held or sustained, and the
                 // previous note was played while in valid legato mode.
                 doinglegato = true; // So we'll do a legato note.
@@ -337,7 +336,7 @@ void Part::NoteOn(unsigned char note,
         // still held down or sustained for the Portamento to activate
         // (that's like Legato).
         int portamento = 0;
-        if((Ppolymode != 0) || (not ismonofirstnote))
+        if((Ppolymode != 0) || (!ismonofirstnote))
             // I added a third argument to the
             // ctl.initportamento(...) function to be able
             // to tell it if we're doing a legato note.
@@ -629,13 +628,13 @@ void Part::NoteOff(unsigned char note) //release the key
     int i;
 
     // This note is released, so we remove it from the list.
-    if(not monomemnotes.empty())
+    if(!monomemnotes.empty())
         monomemnotes.remove(note);
 
     for(i = POLIPHONY - 1; i >= 0; i--) //first note in, is first out if there are same note multiple times
         if((partnote[i].status == KEY_PLAYING) && (partnote[i].note == note)) {
             if(ctl.sustain.sustain == 0) { //the sustain pedal is not pushed
-                if((Ppolymode == 0) && (not monomemnotes.empty()))
+                if((Ppolymode == 0) && (!monomemnotes.empty()))
                     MonoMemRenote();  // To play most recent still held note.
                 else
                     RelaseNotePos(i);
@@ -796,7 +795,7 @@ void Part::SetController(unsigned int type, int par)
 void Part::RelaseSustainedKeys()
 {
     // Let's call MonoMemRenote() on some conditions:
-    if((Ppolymode == 0) && (not monomemnotes.empty()))
+    if((Ppolymode == 0) && (!monomemnotes.empty()))
         if(monomemnotes.back() != lastnote) // Sustain controller manipulation would cause repeated same note respawn without this check.
             MonoMemRenote();  // To play most recent still held note.
 
@@ -947,8 +946,13 @@ void Part::RunNote(unsigned int k)
                 continue;
             noteplay++;
 
+#ifdef _MSC_VER
+            const auto tmpoutr = static_cast<float*>(_alloca(synth->buffersize * sizeof(float)));
+            const auto tmpoutl = static_cast<float*>(_alloca(synth->buffersize * sizeof(float)));
+#else
             float tmpoutr[synth->buffersize];
             float tmpoutl[synth->buffersize];
+#endif
             (*note)->noteout(&tmpoutl[0], &tmpoutr[0]);
 
             if((*note)->finished()) {
diff --git a/src/Misc/Part.h b/src/Misc/Part.h
index ed247d30..f6e50155 100644
--- a/src/Misc/Part.h
+++ b/src/Misc/Part.h
@@ -29,7 +29,7 @@
 #include "../Params/Controller.h"
 #include "../Misc/Microtonal.h"
 
-#include <pthread.h>
+#include "ThreadShims.h"
 #include <list> // For the monomemnotes list.
 
 class EffectMgr;
@@ -47,8 +47,8 @@ class Part
         /**Constructor
          * @param microtonal_ Pointer to the microtonal object
          * @param fft_ Pointer to the FFTwrapper
-         * @param mutex_ Pointer to the master pthread_mutex_t*/
-        Part(Microtonal *microtonal_, FFTwrapper *fft_, pthread_mutex_t *mutex_);
+         * @param mutex_ Pointer to the master std::mutex*/
+        Part(Microtonal *microtonal_, FFTwrapper *fft_, std::mutex *mutex_);
         /**Destructor*/
         ~Part();
 
@@ -152,8 +152,8 @@ class Part
         bool Pefxbypass[NUM_PART_EFX]; //if the effects are bypassed
 
 
-        pthread_mutex_t *mutex;
-        pthread_mutex_t load_mutex;
+        std::mutex *mutex;
+        std::mutex load_mutex;
 
         int lastnote;
 
diff --git a/src/Misc/Util.cpp b/src/Misc/Util.cpp
index 9025c622..24c14319 100644
--- a/src/Misc/Util.cpp
+++ b/src/Misc/Util.cpp
@@ -32,7 +32,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
-#include <unistd.h>
+#include "ThreadShims.h"
 #include <errno.h>
 #include <string.h>
 #ifdef HAVE_SCHEDULER
@@ -135,7 +135,7 @@ void set_realtime()
 
 void os_sleep(long length)
 {
-    usleep(length);
+    std::this_thread::sleep_for(std::chrono::microseconds{length});
 }
 
 std::string legalizeFilename(std::string filename)
diff --git a/src/Nio/CMakeLists.txt b/src/Nio/CMakeLists.txt
index 9386610b..f2c12212 100644
--- a/src/Nio/CMakeLists.txt
+++ b/src/Nio/CMakeLists.txt
@@ -42,6 +42,6 @@ if(OssEnable)
 endif(OssEnable)
 
 
-add_library(zynaddsubfx_nio STATIC
+add_library(zynaddsubfx_nio OBJECT
     ${zynaddsubfx_nio_SRCS} 
     )
diff --git a/src/Nio/InMgr.cpp b/src/Nio/InMgr.cpp
index 441a6dcd..b4eb15cd 100644
--- a/src/Nio/InMgr.cpp
+++ b/src/Nio/InMgr.cpp
@@ -44,7 +44,7 @@ InMgr::InMgr()
     :queue(100), master(Master::getInstance())
 {
     current = NULL;
-    work.init(PTHREAD_PROCESS_PRIVATE, 0);
+    work.init(0, 0);
 }
 
 InMgr::~InMgr()
diff --git a/src/Nio/NulEngine.cpp b/src/Nio/NulEngine.cpp
index 633e2ae2..ee2cac81 100644
--- a/src/Nio/NulEngine.cpp
+++ b/src/Nio/NulEngine.cpp
@@ -23,17 +23,16 @@
 #include "NulEngine.h"
 #include "../globals.h"
 
-#include <unistd.h>
 #include <iostream>
 
 using namespace std;
+using Clock = std::chrono::steady_clock;
 
 NulEngine::NulEngine()
     :AudioOut(), pThread(NULL)
 {
     name = "NULL";
-    playing_until.tv_sec  = 0;
-    playing_until.tv_usec = 0;
+    playing_until = Clock::time_point::min();
 }
 
 void *NulEngine::_AudioThread(void *arg)
@@ -46,28 +45,24 @@ void *NulEngine::AudioThread()
     while(pThread) {
         getNext();
 
-        struct timeval now;
-        int remaining = 0;
-        gettimeofday(&now, NULL);
-        if((playing_until.tv_usec == 0) && (playing_until.tv_sec == 0)) {
-            playing_until.tv_usec = now.tv_usec;
-            playing_until.tv_sec  = now.tv_sec;
+        using namespace std::literals::chrono_literals;
+        const auto now = Clock::now();
+        auto remaining = Clock::duration{};
+        if(playing_until == Clock::time_point::min()) {
+            playing_until = now;
         }
         else {
-            remaining = (playing_until.tv_usec - now.tv_usec)
-                        + (playing_until.tv_sec - now.tv_sec) * 1000000;
-            if(remaining > 10000) //Don't sleep() less than 10ms.
+            remaining = playing_until - now;
+            if(remaining > 10ms) //Don't sleep() less than 10ms.
                 //This will add latency...
-                usleep(remaining - 10000);
-            if(remaining < 0)
+                std::this_thread::sleep_for(remaining - 10ms);
+            if(remaining < 0ms)
                 cerr << "WARNING - too late" << endl;
         }
-        playing_until.tv_usec += synth->buffersize * 1000000
+        playing_until += synth->buffersize * std::chrono::duration_cast<Clock::duration>(1s)
                                  / synth->samplerate;
-        if(remaining < 0)
-            playing_until.tv_usec -= remaining;
-        playing_until.tv_sec  += playing_until.tv_usec / 1000000;
-        playing_until.tv_usec %= 1000000;
+        if(remaining < 0ms)
+            playing_until -= remaining;
     }
     return NULL;
 }
@@ -90,19 +85,14 @@ void NulEngine::setAudioEn(bool nval)
 {
     if(nval) {
         if(!getAudioEn()) {
-            pthread_t     *thread = new pthread_t;
-            pthread_attr_t attr;
-            pthread_attr_init(&attr);
-            pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
-            pThread = thread;
-            pthread_create(pThread, &attr, _AudioThread, this);
+            pThread = new std::thread{_AudioThread, this};
         }
     }
     else
     if(getAudioEn()) {
-        pthread_t *thread = pThread;
+        std::thread *thread = pThread;
         pThread = NULL;
-        pthread_join(*thread, NULL);
+        thread->join();
         delete thread;
     }
 }
diff --git a/src/Nio/NulEngine.h b/src/Nio/NulEngine.h
index 18341809..a363e4c2 100644
--- a/src/Nio/NulEngine.h
+++ b/src/Nio/NulEngine.h
@@ -23,8 +23,8 @@
 #ifndef NUL_ENGINE_H
 #define NUL_ENGINE_H
 
-#include <sys/time.h>
-#include <pthread.h>
+#include <chrono>
+#include "ThreadShims.h"
 #include "../globals.h"
 #include "AudioOut.h"
 #include "MidiIn.h"
@@ -49,8 +49,8 @@ class NulEngine:public AudioOut, MidiIn
         static void *_AudioThread(void *arg);
 
     private:
-        struct timeval playing_until;
-        pthread_t     *pThread;
+        std::chrono::steady_clock::time_point playing_until;
+        std::thread *pThread;
 };
 
 #endif
diff --git a/src/Nio/OutMgr.cpp b/src/Nio/OutMgr.cpp
index 7fbe2417..ef94513d 100644
--- a/src/Nio/OutMgr.cpp
+++ b/src/Nio/OutMgr.cpp
@@ -26,7 +26,6 @@ OutMgr::OutMgr()
 {
     currentOut = NULL;
     stales     = 0;
-    master     = Master::getInstance();
 
     //init samples
     outr = new float[synth->buffersize];
@@ -61,13 +60,13 @@ const Stereo<float *> OutMgr::tick(unsigned int frameSize)
     int i=0;
     while(frameSize > storedSmps()) {
         if(!midi.empty()) {
-            pthread_mutex_lock(&(master.mutex));
+            master.mutex.lock();
             midi.flush(i*synth->buffersize, (i+1)*synth->buffersize);
-            pthread_mutex_unlock(&(master.mutex));
+            master.mutex.unlock();
         }
-        pthread_mutex_lock(&(master.mutex));
+        master.mutex.lock();
         master.AudioOut(outl, outr);
-        pthread_mutex_unlock(&(master.mutex));
+        master.mutex.unlock();
         addSmps(outl, outr);
         i++;
     }
diff --git a/src/Nio/OutMgr.h b/src/Nio/OutMgr.h
index bc3a922d..b503b100 100644
--- a/src/Nio/OutMgr.h
+++ b/src/Nio/OutMgr.h
@@ -4,8 +4,6 @@
 #include "../Misc/Stereo.h"
 #include <list>
 #include <string>
-#include <pthread.h>
-#include <semaphore.h>
 
 
 class AudioOut;
@@ -49,8 +47,6 @@ class OutMgr
 
         AudioOut *currentOut; /**<The current output driver*/
 
-        sem_t requested;
-
         /**Buffer*/
         Stereo<float *> priBuf;          //buffer for primary drivers
         Stereo<float *> priBuffCurrent; //current array accessor
diff --git a/src/Nio/SafeQueue.cpp b/src/Nio/SafeQueue.cpp
index 510e4b20..db1951bb 100644
--- a/src/Nio/SafeQueue.cpp
+++ b/src/Nio/SafeQueue.cpp
@@ -3,8 +3,8 @@ template<class T>
 SafeQueue<T>::SafeQueue(size_t maxlen)
     :writePtr(0), readPtr(0), bufSize(maxlen)
 {
-    w_space.init(PTHREAD_PROCESS_PRIVATE, maxlen - 1);
-    r_space.init(PTHREAD_PROCESS_PRIVATE, 0);
+    w_space.init(0, maxlen - 1);
+    r_space.init(0, 0);
     buffer = new T[maxlen];
 }
 
diff --git a/src/Nio/SafeQueue.h b/src/Nio/SafeQueue.h
index 9bba53a6..dcebd253 100644
--- a/src/Nio/SafeQueue.h
+++ b/src/Nio/SafeQueue.h
@@ -3,8 +3,6 @@
 #define SAFEQUEUE_H
 #include <cstdlib>
 #include "ZynSema.h"
-#include <pthread.h>
-#include <semaphore.h>
 
 /**
  * C++ thread safe lockless queue
diff --git a/src/Nio/WavEngine.cpp b/src/Nio/WavEngine.cpp
index 1c3d66ec..2c3a31e4 100644
--- a/src/Nio/WavEngine.cpp
+++ b/src/Nio/WavEngine.cpp
@@ -28,7 +28,7 @@ using namespace std;
 WavEngine::WavEngine()
     :AudioOut(), file(NULL), buffer(synth->samplerate * 4), pThread(NULL)
 {
-    work.init(PTHREAD_PROCESS_PRIVATE, 0);
+    work.init(0, 0);
 }
 
 WavEngine::~WavEngine()
@@ -46,12 +46,7 @@ bool WavEngine::Start()
 {
     if(pThread)
         return true;
-    pThread = new pthread_t;
-
-    pthread_attr_t attr;
-    pthread_attr_init(&attr);
-    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
-    pthread_create(pThread, &attr, _AudioThread, this);
+    pThread = new std::thread{_AudioThread, this};
 
     return true;
 }
@@ -61,11 +56,11 @@ void WavEngine::Stop()
     if(!pThread)
         return;
 
-    pthread_t *tmp = pThread;
+    std::thread *tmp = pThread;
     pThread = NULL;
 
     work.post();
-    pthread_join(*tmp, NULL);
+    tmp->join();
     delete pThread;
 }
 
diff --git a/src/Nio/WavEngine.h b/src/Nio/WavEngine.h
index 73f553c9..2e786e8a 100644
--- a/src/Nio/WavEngine.h
+++ b/src/Nio/WavEngine.h
@@ -24,7 +24,7 @@
 #define WAVENGINE_H
 #include "AudioOut.h"
 #include <string>
-#include <pthread.h>
+#include "ThreadShims.h"
 #include "ZynSema.h"
 #include "SafeQueue.h"
 
@@ -56,6 +56,6 @@ class WavEngine:public AudioOut
         ZynSema  work;
         SafeQueue<float> buffer;
 
-        pthread_t *pThread;
+        std::thread *pThread;
 };
 #endif
diff --git a/src/Nio/ZynSema.h b/src/Nio/ZynSema.h
index c41477e0..b4b36943 100644
--- a/src/Nio/ZynSema.h
+++ b/src/Nio/ZynSema.h
@@ -3,7 +3,7 @@
 
 #if defined __APPLE__ || defined WIN32
 
-#include <pthread.h>
+#include "ThreadShims.h"
 
 class ZynSema
 {
@@ -12,45 +12,38 @@ class ZynSema
     {
     }
 
-    ~ZynSema (void)
-    {
-        pthread_mutex_destroy (&_mutex);
-        pthread_cond_destroy (&_cond);
-    }
-
     int init (int, int v)
     {
         _count = v;
-        return pthread_mutex_init (&_mutex, 0) || pthread_cond_init (&_cond, 0);
+        return 0;
     }
 
     int post (void)
     {
-        pthread_mutex_lock (&_mutex);
-        if (++_count == 1) pthread_cond_signal (&_cond);
-        pthread_mutex_unlock (&_mutex);
+        _mutex.lock();
+        if (++_count == 1) _cond.notify_one();
+        _mutex.unlock();
         return 0;
     }
 
     int wait (void)
     {
-        pthread_mutex_lock (&_mutex);
-        while (_count < 1) pthread_cond_wait (&_cond, &_mutex);
+        auto lock = std::unique_lock{_mutex};
+        while (_count < 1) _cond.wait(lock);
         --_count;
-        pthread_mutex_unlock (&_mutex);
         return 0;
     }
 
     int trywait (void)
     {
-        if (pthread_mutex_trylock (&_mutex)) return -1;
+        if (!_mutex.try_lock()) return -1;
         if (_count < 1)
         {
-            pthread_mutex_unlock (&_mutex);
+            _mutex.unlock();
             return -1;
         }
         --_count;
-        pthread_mutex_unlock (&_mutex);
+        _mutex.unlock();
         return 0;
     }
 
@@ -62,8 +55,8 @@ class ZynSema
 
 private:
     int              _count;
-    pthread_mutex_t  _mutex;
-    pthread_cond_t   _cond;
+    std::mutex _mutex;
+    std::condition_variable _cond;
 };
 
 #else // POSIX sempahore
diff --git a/src/Params/PADnoteParameters.cpp b/src/Params/PADnoteParameters.cpp
index 5d4af3d1..31437b17 100644
--- a/src/Params/PADnoteParameters.cpp
+++ b/src/Params/PADnoteParameters.cpp
@@ -24,7 +24,7 @@
 #include "../Misc/WavFile.h"
 
 PADnoteParameters::PADnoteParameters(FFTwrapper *fft_,
-                                     pthread_mutex_t *mutex_):Presets()
+                                     std::mutex *mutex_):Presets()
 {
     setpresettype("Ppadsynth");
 
@@ -395,7 +395,11 @@ void PADnoteParameters::generatespectrum_bandwidthMode(float *spectrum,
     for(int i = 0; i < size; ++i)
         spectrum[i] = 0.0f;
 
+#ifdef _MSC_VER
+    const auto harmonics = static_cast<float*>(_alloca(synth->oscilsize / 2 * sizeof(float)));
+#else
     float harmonics[synth->oscilsize / 2];
+#endif
     for(int i = 0; i < synth->oscilsize / 2; ++i)
         harmonics[i] = 0.0f;
     //get the harmonic structure from the oscillator (I am using the frequency amplitudes, only)
@@ -503,7 +507,11 @@ void PADnoteParameters::generatespectrum_otherModes(float *spectrum,
     for(int i = 0; i < size; ++i)
         spectrum[i] = 0.0f;
 
+#ifdef _MSC_VER
+    const auto harmonics = static_cast<float*>(_alloca(synth->oscilsize / 2 * sizeof(float)));
+#else
     float harmonics[synth->oscilsize / 2];
+#endif
     for(int i = 0; i < synth->oscilsize / 2; ++i)
         harmonics[i] = 0.0f;
     //get the harmonic structure from the oscillator (I am using the frequency amplitudes, only)
@@ -565,7 +573,11 @@ void PADnoteParameters::applyparameters(bool lockmutex)
     int       spectrumsize = samplesize / 2;
     float    *spectrum     = new float[spectrumsize];
     int       profilesize = 512;
+#ifdef _MSC_VER
+    const auto profile = static_cast<float*>(_alloca(profilesize * sizeof(float)));
+#else
     float     profile[profilesize];
+#endif
 
 
     float bwadjust = getprofile(profile, profilesize);
@@ -591,7 +603,11 @@ void PADnoteParameters::applyparameters(bool lockmutex)
     FFTwrapper *fft      = new FFTwrapper(samplesize);
     fft_t      *fftfreqs = new fft_t[samplesize / 2];
 
+#ifdef _MSC_VER
+    const auto adj = static_cast<float*>(_alloca(samplemax * sizeof(float)));
+#else
     float adj[samplemax]; //this is used to compute frequency relation to the base frequency
+#endif
     for(int nsample = 0; nsample < samplemax; ++nsample)
         adj[nsample] = (Pquality.oct + 1.0f) * (float)nsample / samplemax;
     for(int nsample = 0; nsample < samplemax; ++nsample) {
@@ -637,12 +653,12 @@ void PADnoteParameters::applyparameters(bool lockmutex)
 
         //replace the current sample with the new computed sample
         if(lockmutex) {
-            pthread_mutex_lock(mutex);
+            mutex->lock();
             deletesample(nsample);
             sample[nsample].smp      = newsample.smp;
             sample[nsample].size     = samplesize;
             sample[nsample].basefreq = basefreq * basefreqadjust;
-            pthread_mutex_unlock(mutex);
+            mutex->unlock();
         }
         else {
             deletesample(nsample);
@@ -658,10 +674,10 @@ void PADnoteParameters::applyparameters(bool lockmutex)
 
     //delete the additional samples that might exists and are not useful
     if(lockmutex) {
-        pthread_mutex_lock(mutex);
+        mutex->lock();
         for(int i = samplemax; i < PAD_MAX_SAMPLES; ++i)
             deletesample(i);
-        pthread_mutex_unlock(mutex);
+        mutex->unlock();
     }
     else
         for(int i = samplemax; i < PAD_MAX_SAMPLES; ++i)
diff --git a/src/Params/PADnoteParameters.h b/src/Params/PADnoteParameters.h
index b3283216..ad3c8c8d 100644
--- a/src/Params/PADnoteParameters.h
+++ b/src/Params/PADnoteParameters.h
@@ -35,12 +35,12 @@
 #include "FilterParams.h"
 #include "Presets.h"
 #include <string>
-#include <pthread.h>
+#include "ThreadShims.h"
 
 class PADnoteParameters:public Presets
 {
     public:
-        PADnoteParameters(FFTwrapper *fft_, pthread_mutex_t *mutex_);
+        PADnoteParameters(FFTwrapper *fft_, std::mutex *mutex_);
         ~PADnoteParameters();
 
         void defaults();
@@ -171,7 +171,7 @@ class PADnoteParameters:public Presets
         void deletesample(int n);
 
         FFTwrapper *fft;
-        pthread_mutex_t *mutex;
+        std::mutex *mutex;
 };
 
 
diff --git a/src/Synth/ADnote.cpp b/src/Synth/ADnote.cpp
index 201a6771..df64aad8 100644
--- a/src/Synth/ADnote.cpp
+++ b/src/Synth/ADnote.cpp
@@ -136,7 +136,11 @@ ADnote::ADnote(ADnoteParameters *pars,
             };
                 break;
             default: { //unison for more than 2 subvoices
+#ifdef _MSC_VER
+                const auto unison_values = static_cast<float*>(_alloca(unison * sizeof(float)));
+#else
                 float unison_values[unison];
+#endif
                 float min = -1e-6, max = 1e-6;
                 for(int k = 0; k < unison; ++k) {
                     float step = (k / (float) (unison - 1)) * 2.0f - 1.0f; //this makes the unison spread more uniform
diff --git a/src/Synth/OscilGen.cpp b/src/Synth/OscilGen.cpp
index d3f39a12..df179d6e 100644
--- a/src/Synth/OscilGen.cpp
+++ b/src/Synth/OscilGen.cpp
@@ -25,6 +25,7 @@
 
 #include <cassert>
 #include <stdlib.h>
+#define _USE_MATH_DEFINES
 #include <math.h>
 #include <stdio.h>
 
@@ -203,7 +204,11 @@ void OscilGen::defaults()
 void OscilGen::convert2sine()
 {
     float  mag[MAX_AD_HARMONICS], phase[MAX_AD_HARMONICS];
+#ifdef _MSC_VER
+    const auto oscil = static_cast<float*>(_alloca(synth->oscilsize * sizeof(float)));
+#else
     float  oscil[synth->oscilsize];
+#endif
     fft_t *freqs = new fft_t[synth->oscilsize / 2];
 
     get(oscil, -1.0f);
diff --git a/src/Synth/SUBnote.cpp b/src/Synth/SUBnote.cpp
index 2f352afb..cc2975b4 100644
--- a/src/Synth/SUBnote.cpp
+++ b/src/Synth/SUBnote.cpp
@@ -20,6 +20,7 @@
 
 */
 
+#define _USE_MATH_DEFINES
 #include <cmath>
 #include <cstdlib>
 #include <cstdio>
@@ -505,8 +506,13 @@ int SUBnote::noteout(float *outl, float *outr)
     if(NoteEnabled == OFF)
         return 0;
 
+#ifdef _MSC_VER
+    const auto tmprnd = static_cast<float*>(_alloca(synth->buffersize * sizeof(float)));
+    const auto tmpsmp = static_cast<float*>(_alloca(synth->buffersize * sizeof(float)));
+#else
     float tmprnd[synth->buffersize];
     float tmpsmp[synth->buffersize];
+#endif
     //left channel
     for(int i = 0; i < synth->buffersize; ++i)
         tmprnd[i] = RND * 2.0f - 1.0f;
diff --git a/src/UI/BankUI.fl b/src/UI/BankUI.fl
index a7eab825..a7aa98e1 100644
--- a/src/UI/BankUI.fl
+++ b/src/UI/BankUI.fl
@@ -265,9 +265,9 @@ if ((what==2)&&(bank->emptyslot(slot)==0)&&(mode!=4)) {//Rename slot
 };
 
 if ((what==1)&&(mode==1)&&(!bank->emptyslot(slot))){//Reads from slot
-    pthread_mutex_lock(&master->part[*npart]->load_mutex);
+    master->part[*npart]->load_mutex.lock();
      bank->loadfromslot(slot,master->part[*npart]);
-    pthread_mutex_unlock(&master->part[*npart]->load_mutex);
+    master->part[*npart]->load_mutex.unlock();
     master->part[*npart]->applyparameters();
     snprintf((char *)master->part[*npart]->Pname,PART_MAX_NAME_LEN,"%s",bank->getname(slot).c_str());
      cbwig->do_callback();
@@ -281,9 +281,9 @@ if ((what==1)&&(mode==2)){//save(write) to slot
      if (!bank->emptyslot(slot)){
        if (!fl_choice("Overwrite the slot no. %d ?","No","Yes",NULL,slot+1)) goto nooverwriteslot;
       };
-       pthread_mutex_lock(&master->part[*npart]->load_mutex);
+       master->part[*npart]->load_mutex.lock();
         bank->savetoslot(slot,master->part[*npart]);
-       pthread_mutex_unlock(&master->part[*npart]->load_mutex);
+       master->part[*npart]->load_mutex.unlock();
 
        bs[slot]->refresh();
        mode=1;readbutton->value(1);writebutton->value(0);
diff --git a/src/UI/CMakeLists.txt b/src/UI/CMakeLists.txt
index 38ea1e11..723d8b88 100644
--- a/src/UI/CMakeLists.txt
+++ b/src/UI/CMakeLists.txt
@@ -29,7 +29,7 @@ if(LibloEnable)
     set(zynaddsubfx_gui_FLTK_UI_SRCS ${zynaddsubfx_gui_FLTK_UI_SRCS} NSM.C NSM/Client.C)
 endif()
 
-add_library(zynaddsubfx_gui STATIC
+add_library(zynaddsubfx_gui OBJECT
 	${UI_objs}
 	${zynaddsubfx_gui_FLTK_UI_SRCS}
         NioUI.cpp
diff --git a/src/UI/MasterUI.fl b/src/UI/MasterUI.fl
index 641f8321..c537e22f 100644
--- a/src/UI/MasterUI.fl
+++ b/src/UI/MasterUI.fl
@@ -92,7 +92,7 @@ int ox=x(); int oy=y(); int lx=w(); int ly=h();
 
 vuData data = master->getVuData();
 
-//pthread_mutex_lock(&master->mutex);
+//master->mutex.lock();
 float dbl=rap2dB(data.outpeakl);
 float dbr=rap2dB(data.outpeakr);
 float rmsdbl=rap2dB(data.rmspeakl);
@@ -100,7 +100,7 @@ float rmsdbr=rap2dB(data.rmspeakr);
 float maxdbl=rap2dB(data.maxoutpeakl);
 float maxdbr=rap2dB(data.maxoutpeakr);
 int clipped=data.clipped;
-//pthread_mutex_unlock(&master->mutex);
+//master->mutex.unlock();
 
 dbl=(MIN_DB-dbl)/MIN_DB; 
 if (dbl<0.0) dbl=0.0;
@@ -198,9 +198,9 @@ if ((maxdbr>MIN_DB-20)){
 int ox=x(); int oy=y(); int lx=w(); int ly=h();
 
 if (!active_r()){
-  pthread_mutex_lock(&master->vumutex);
+  master->vumutex.lock();
    int fakedb=master->fakepeakpart[npart];
-  pthread_mutex_unlock(&master->vumutex);
+  master->vumutex.unlock();
   fl_rectf(ox,oy,lx,ly,140,140,140);
   if (fakedb>0){
     fakedb=(int)(fakedb/255.0*ly)+4;
@@ -211,9 +211,9 @@ if (!active_r()){
 };
 
 //draw the vu lines
-pthread_mutex_lock(&master->vumutex);
+master->vumutex.lock();
  float db=rap2dB(master->vuoutpeakpart[npart]);
-pthread_mutex_unlock(&master->vumutex);
+master->vumutex.unlock();
 
 db=(MIN_DB-db)/MIN_DB; 
 if (db<0.0) db=0.0;
@@ -259,9 +259,9 @@ float  tmp=ly*1.0/MIN_DB;
              break;
    case FL_PUSH:
              if (npart>=0) break;
-             pthread_mutex_lock(&master->mutex);
+             master->mutex.lock();
              master->vuresetpeaks();
-             pthread_mutex_unlock(&master->mutex);
+             master->mutex.unlock();
              break;
 };
 return(1);} {}
@@ -370,9 +370,9 @@ bankui->show();}
       }
       Fl_Check_Button partenabled {
         label 01
-        callback {pthread_mutex_lock(&master->mutex);
+        callback {master->mutex.lock();
  master->partonoff(npart,(int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 if ((int) o->value()==0) panellistitemgroup->deactivate();
   else {
@@ -499,13 +499,13 @@ class MasterUI {open
 filename=fl_file_chooser("Open:","({*.xsz})",NULL,0);
 if (filename==NULL) return;
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
   //clear all parameters
   master->microtonal.defaults();
 
   //load the data
   int result=master->microtonal.loadXML(filename);
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 
  delete microtonalui;  
@@ -532,9 +532,9 @@ if (result) {
 };
 
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 result=master->microtonal.saveXML(filename);
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 if (result<0) fl_alert("Error: Could not save the file.");
 
@@ -577,9 +577,9 @@ nioui.show();}
             label {&Clear Instrument...}
             callback {if (fl_choice("Clear instrument's parameters ?","No","Yes",NULL)){
 //       int npart=(int)npartcounter->value()-1;
-       pthread_mutex_lock(&master->mutex);
+       master->mutex.lock();
        master->part[npart]->defaultsinstrument();
-       pthread_mutex_unlock(&master->mutex);
+       master->mutex.unlock();
 
        npartcounter->do_callback();
 };
@@ -594,7 +594,7 @@ filename=fl_file_chooser("Load:","({*.xiz})",NULL,0);
 if (filename==NULL) return;
 
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 //  int npart=(int)npartcounter->value()-1;
 
   //clear all instrument parameters, first
@@ -603,7 +603,7 @@ pthread_mutex_lock(&master->mutex);
   //load the instr. parameters
   int result=master->part[npart]->loadXMLinstrument(filename);
 
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 master->part[npart]->applyparameters();
 
 npartcounter->do_callback();
@@ -629,9 +629,9 @@ if (result) {
 };
 
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 result=master->part[npart]->saveXML(filename);
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 if (result<0) fl_alert("Error: Could not save the file.");
 
@@ -709,9 +709,9 @@ if (result!=0) fl_alert("Error: Could not save the file.");}
       Fl_Button {} {
         label {Panic!}
         callback {virkeyboard->relaseallkeys();
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 master->shutup=1;
-pthread_mutex_unlock(&master->mutex);}
+master->mutex.unlock();}
         xywh {280 29 105 53} color 90 labelfont 1
       }
       Fl_Group partuigroup {open
@@ -742,9 +742,9 @@ syseffectui->refresh(master->sysefx[nsyseff]);}
           }
           Fl_Choice sysefftype {
             label EffType
-            callback {pthread_mutex_lock(&master->mutex);
+            callback {master->mutex.lock();
 master->sysefx[nsyseff]->changeeffect((int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 syseffectui->refresh(master->sysefx[nsyseff]);}
             xywh {285 176 100 22} down_box BORDER_BOX labelsize 10
             code0 {o->value(master->sysefx[nsyseff]->geteffect());}
@@ -807,9 +807,9 @@ syseffectui->refresh(master->sysefx[nsyseff]);}
           }
           Fl_Button {} {
             label P
-            callback {pthread_mutex_lock(&master->mutex);
+            callback {master->mutex.lock();
 presetsui->paste(master->sysefx[nsyseff],syseffectui);
-pthread_mutex_unlock(&master->mutex);}
+master->mutex.unlock();}
             xywh {210 187 25 15} box THIN_UP_BOX color 179 labelfont 1 labelsize 11 labelcolor 55
           }
         }
@@ -839,9 +839,9 @@ if (master->Pinsparts[ninseff]!=-1) {
           }
           Fl_Choice insefftype {
             label EffType
-            callback {pthread_mutex_lock(&master->mutex);
+            callback {master->mutex.lock();
 master->insefx[ninseff]->changeeffect((int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 inseffectui->refresh(master->insefx[ninseff]);
 inseffectui->show();}
             xywh {285 173 100 22} down_box BORDER_BOX labelsize 10
@@ -920,9 +920,9 @@ master->insefx[ninseff]->cleanup();} open
           }
           Fl_Button {} {
             label P
-            callback {pthread_mutex_lock(&master->mutex);
+            callback {master->mutex.lock();
 presetsui->paste(master->insefx[ninseff],inseffectui);
-pthread_mutex_unlock(&master->mutex);}
+master->mutex.unlock();}
             xywh {210 185 25 15} box THIN_UP_BOX color 179 labelfont 1 labelsize 11 labelcolor 55
           }
         }
@@ -1188,7 +1188,7 @@ filename=fl_file_chooser("Load:","({*.xiz})",NULL,0);
 if (filename==NULL) return;
 
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 //  int npart=(int)npartcounter->value()-1;
 
   //clear all instrument parameters, first
@@ -1197,7 +1197,7 @@ pthread_mutex_lock(&master->mutex);
   //load the instr. parameters
   int result=master->part[npart]->loadXMLinstrument(filename);
 
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 master->part[npart]->applyparameters();
 
 simplenpartcounter->do_callback();
@@ -1329,9 +1329,9 @@ simplemaxkcounter->do_callback();}
       }
       Fl_Check_Button partenabled {
         label Enabled
-        callback {pthread_mutex_lock(&master->mutex);
+        callback {master->mutex.lock();
  master->partonoff(npart,(int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 if ((int) o->value()==0) simplelistitemgroup->deactivate();
   else {
@@ -1375,9 +1375,9 @@ simplerefresh();}
             }
             Fl_Choice simplesysefftype {
               label EffType
-              callback {pthread_mutex_lock(&master->mutex);
+              callback {master->mutex.lock();
 master->sysefx[nsyseff]->changeeffect((int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 simplesyseffectui->refresh(master->sysefx[nsyseff]);}
               xywh {515 80 70 15} down_box BORDER_BOX labelsize 10 align 5
               code0 {o->value(master->sysefx[nsyseff]->geteffect());}
@@ -1435,9 +1435,9 @@ simplesyseffectui->refresh(master->sysefx[nsyseff]);}
             }
             Fl_Button {} {
               label P
-              callback {pthread_mutex_lock(&master->mutex);
+              callback {master->mutex.lock();
 presetsui->paste(master->sysefx[nsyseff],simplesyseffectui);
-pthread_mutex_unlock(&master->mutex);}
+master->mutex.unlock();}
               xywh {560 65 25 15} box THIN_UP_BOX color 179 labelfont 1 labelsize 11 labelcolor 55
             }
           }
@@ -1467,9 +1467,9 @@ if (master->Pinsparts[ninseff]!=-1) {
             }
             Fl_Choice simpleinsefftype {
               label EffType
-              callback {pthread_mutex_lock(&master->mutex);
+              callback {master->mutex.lock();
 master->insefx[ninseff]->changeeffect((int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 simpleinseffectui->refresh(master->insefx[ninseff]);
 simpleinseffectui->show();}
               xywh {515 80 70 15} down_box BORDER_BOX labelsize 10 align 5
@@ -1543,9 +1543,9 @@ master->insefx[ninseff]->cleanup();} open
             } {}
             Fl_Button {} {
               label P
-              callback {pthread_mutex_lock(&master->mutex);
+              callback {master->mutex.lock();
 presetsui->paste(master->insefx[ninseff],simpleinseffectui);
-pthread_mutex_unlock(&master->mutex);}
+master->mutex.unlock();}
               xywh {560 65 25 15} box THIN_UP_BOX color 179 labelfont 1 labelsize 11 labelcolor 55
             }
           }
@@ -1578,9 +1578,9 @@ pthread_mutex_unlock(&master->mutex);}
       Fl_Button {} {
         label {Stop ALL sounds!}
         callback {virkeyboard->relaseallkeys();
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 master->shutup=1;
-pthread_mutex_unlock(&master->mutex);}
+master->mutex.unlock();}
         xywh {5 149 115 31} color 90 labelfont 1 labelsize 10
       }
       Fl_Button {} {
@@ -1756,9 +1756,9 @@ simplesyseffsend->value(master->Psysefxvol[nsyseff][npart]);} {}
   Function {do_new_master_unconditional()} {} {
     code {delete microtonalui;
 
-       pthread_mutex_lock(&master->mutex);
+       master->mutex.lock();
 	master->defaults();
-       pthread_mutex_unlock(&master->mutex);
+       master->mutex.unlock();
 	
        npartcounter->value(1);
        refresh_master_ui();
@@ -1771,7 +1771,7 @@ simplesyseffsend->value(master->Psysefxvol[nsyseff][npart]);} {}
   }
   Function {do_load_master_unconditional(const char *filename, const char *display_name)} {return_type int
   } {
-    code {pthread_mutex_lock(&master->mutex);
+    code {master->mutex.lock();
     //clear all parameters
     master->defaults();
     
@@ -1779,7 +1779,7 @@ simplesyseffsend->value(master->Psysefxvol[nsyseff][npart]);} {}
     int result=master->loadXML(filename);
     
     master->applyparameters(false);
-    pthread_mutex_unlock(&master->mutex);
+    master->mutex.unlock();
     
     npartcounter->value(1);
     refresh_master_ui();
@@ -1825,9 +1825,9 @@ char *tmp;
   }
 
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 result=master->saveXML(filename);
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 if (result<0) fl_alert("Error: Could not save the file.");
 	else
diff --git a/src/UI/OscilGenUI.fl b/src/UI/OscilGenUI.fl
index 54329db5..14a1f90c 100644
--- a/src/UI/OscilGenUI.fl
+++ b/src/UI/OscilGenUI.fl
@@ -74,10 +74,10 @@ float x;
 float* spc=new float[n];
 for (i=0;i<n;i++) spc[i]=0.0;
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 if (oscbase==0) oscil->getspectrum(n,spc,0);
     else oscil->getspectrum(n,spc,1);
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 //normalize
 float max=0;
@@ -186,11 +186,15 @@ master=master_;} {}
   Function {draw()} {open
   } {
     code {int ox=x(),oy=y(),lx=w(),ly=h()-1,i;
+\#ifdef _MSC_VER
+const auto smps = static_cast<float*>(_alloca(synth->oscilsize * sizeof(float)));
+\#else
 float smps[synth->oscilsize];
-pthread_mutex_lock(&master->mutex);
+\#endif
+master->mutex.lock();
 if (oscbase==0) oscil->get(smps,-1.0);
     else oscil->getcurrentbasefunction(smps);
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 if (damage()!=1){
  fl_color( fl_color_average( FL_BLACK, FL_BACKGROUND_COLOR, 0.5 ));
@@ -262,14 +266,14 @@ if (Fl::event_button3()) o->value(x);
 if (x==64) o->selection_color(0);
     else o->selection_color(222);
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
  oscil->Phmag[n]=x;
  if (x==64) {
     oscil->Phphase[n]=64;
     phase->value(64);
  };
  oscil->prepare();
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 display->redraw();
 oldosc->redraw();
@@ -288,10 +292,10 @@ if (cbwidget!=NULL) {
 if (Fl::event_button3()) o->value(x);
    else x=(int)o->value();
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
  oscil->Phphase[n]=x;
  oscil->prepare();
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 display->redraw();
 oldosc->redraw();
@@ -644,13 +648,13 @@ if (autoclearbutton->value()){
    sabutton->do_callback();
 };
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
  for (int i=0;i<MAX_AD_HARMONICS;i++){
    if (oscil->Phmag[i]==64) h[i]->mag->selection_color(0);
       else h[i]->mag->selection_color(222);
  };
  oscil->prepare();
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 basefuncdisplaygroup->redraw();
 redrawoscil();}
@@ -681,9 +685,9 @@ for (int i=0;i<MAX_AD_HARMONICS;i++){
 
 //harmonics->redraw();
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
  oscil->prepare();
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 redrawoscil();}
         xywh {670 505 55 15} box THIN_UP_BOX labelfont 1 labelsize 11
@@ -1037,9 +1041,9 @@ redrawoscil();}
         label Sine
         callback {if (!fl_choice("Convert to SINE?","No","Yes",NULL)) return;
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
  oscil->convert2sine();
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 redrawoscil();
 refresh();}
@@ -1125,9 +1129,9 @@ adhrtype->value(oscil->Padaptiveharmonicspar);
 
 for (int i=0;i<MAX_AD_HARMONICS;i++) h[i]->refresh();
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
  oscil->prepare();
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 basefuncdisplaygroup->redraw();
 redrawoscil();} {}
diff --git a/src/UI/PADnoteUI.fl b/src/UI/PADnoteUI.fl
index c79f9e30..9550dbdf 100644
--- a/src/UI/PADnoteUI.fl
+++ b/src/UI/PADnoteUI.fl
@@ -61,7 +61,11 @@ this->pars=pars;} {}
   Function {draw()} {} {
     code {int ox=x(),oy=y(),lx=w(),ly=h();
 if (!visible()) return;
+\#ifdef _MSC_VER
+const auto smps = static_cast<float*>(_alloca(lx * sizeof(float)));
+\#else
 float smps[lx];
+\#endif
 
 float realbw=pars->getprofile(smps,lx);
 bool active=active_r();
@@ -160,12 +164,16 @@ for (int i=1;i<maxharmonic;i++){
 
 
 int n=synth->oscilsize/2;
+\#ifdef _MSC_VER
+const auto spc = static_cast<float*>(_alloca(n * sizeof(float)));
+\#else
 float spc[n];
+\#endif
 for (int i=0;i<n;i++) spc[i]=0.0;
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 pars->oscilgen->getspectrum(n,spc,0);
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 
 //normalize
@@ -177,7 +185,11 @@ for (int i=0;i<n;i++){
 if (max<0.000001) max=1.0;
 max=max*1.05;
 
+\#ifdef _MSC_VER
+const auto spectrum = static_cast<float*>(_alloca(lx * sizeof(float)));
+\#else
 float spectrum[lx];
+\#endif
 for (int i=0;i<lx;i++) spectrum[i]=0;
 
 
diff --git a/src/UI/PartUI.fl b/src/UI/PartUI.fl
index 0040bbf8..7cf57fb5 100644
--- a/src/UI/PartUI.fl
+++ b/src/UI/PartUI.fl
@@ -197,9 +197,9 @@ if (part->kit[n].Ppadenabled!=0) padeditbutton->activate();
         callback {int answer=1;
 if (o->value()==0) answer=fl_choice("Delete the item?","No","Yes",NULL);
 if (answer!=0){
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
  part->setkititemstatus(n,(int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 if (o->value()==0) partkititemgroup->deactivate();
 else partkititemgroup->activate();
@@ -238,9 +238,9 @@ this->redraw();} {
       callback {int answer=1;
 if (o->value()==0) answer=fl_choice("Delete the item?","No","Yes",NULL);
 if (answer!=0){
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
  part->setkititemstatus(n,(int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 
 if (o->value()==0) partkititemgroup->deactivate();
 else partkititemgroup->activate();
@@ -441,9 +441,9 @@ part->setkeylimit(val);} open
       }
       Fl_Check_Button {} {
         label Enabled
-        callback {pthread_mutex_lock(&master->mutex);
+        callback {master->mutex.lock();
 master->partonoff(npart,(int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 if (part->Penabled==0) partgroupui->deactivate();
     else partgroupui->activate();}
         xywh {90 5 75 20} down_box DOWN_BOX labelfont 1 labelsize 11
@@ -654,9 +654,9 @@ sendtochoice->value(x);}
       }
       Fl_Choice insefftype {
         label EffType
-        callback {pthread_mutex_lock(part->mutex);
+        callback {part->mutex->lock();
 part->partefx[ninseff]->changeeffect((int) o->value());
-pthread_mutex_unlock(part->mutex);
+part->mutex->unlock();
 inseffectui->refresh(part->partefx[ninseff]);}
         xywh {155 110 70 15} down_box BORDER_BOX labelsize 10 align 6
         code0 {o->value(part->partefx[ninseff]->geteffect());}
@@ -748,9 +748,9 @@ if (x==2) part->partefx[ninseff]->setdryonly(true);
       }
       Fl_Button {} {
         label P
-        callback {pthread_mutex_lock(&master->mutex);
+        callback {master->mutex.lock();
 presetsui->paste(part->partefx[ninseff],inseffectui);
-pthread_mutex_unlock(&master->mutex);}
+master->mutex.unlock();}
         xywh {120 127 25 15} box THIN_UP_BOX color 179 labelfont 1 labelsize 11 labelcolor 55
       }
     }
diff --git a/src/UI/VirKeyboard.fl b/src/UI/VirKeyboard.fl
index 805e00cf..1a39b1fe 100644
--- a/src/UI/VirKeyboard.fl
+++ b/src/UI/VirKeyboard.fl
@@ -266,9 +266,9 @@ if (rndvelocity!=0){
   vel=midivel*(127.0-rndvelocity)/127.0+RND*rndvelocity;
 };
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 master->noteOn(midich,nk+midioct*12,(int)vel);
-pthread_mutex_unlock(&master->mutex);} {}
+master->mutex.unlock();} {}
   }
   Function {relasekey(int nk,int type)} {} {
     code {if ((nk<0)||(nk>=N_OCT*12)) return;
@@ -280,9 +280,9 @@ pressed[nk]=0;
 
 damage(1);
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 master->noteOff(midich,nk+12*midioct);
-pthread_mutex_unlock(&master->mutex);} {}
+master->mutex.unlock();} {}
   }
   Function {relaseallkeys(int type)} {} {
     code {for (int i=0;i<N_OCT*12;i++) relasekey(i,type);} {}
@@ -356,9 +356,9 @@ virkeyboardwindow->hide();}
         label Cval
         callback {int ctl=midictl;
 
-pthread_mutex_lock(&master->mutex);
+master->mutex.lock();
 master->setController(virkeys->midich,ctl,(int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 virkeys->take_focus();}
         tooltip {Controller value} xywh {605 10 15 115} type {Vert Fill} box ENGRAVED_BOX selection_color 229 labelsize 8 align 5 minimum 127 maximum 0 step 1 value 64 textsize 7
       }
@@ -438,9 +438,9 @@ virkeys->take_focus();}
       }
       Fl_Roller pitchwheelroller {
         label Pwh
-        callback {pthread_mutex_lock(&master->mutex);
+        callback {master->mutex.lock();
 master->setController(virkeys->midich,C_pitchwheel,-(int) o->value());
-pthread_mutex_unlock(&master->mutex);
+master->mutex.unlock();
 virkeys->take_focus();}
         tooltip {Pitch Wheel} xywh {625 10 20 95} labelsize 8 align 1 when 3 minimum -8192 maximum 8192 step 64
       }