diff --git a/src/libraries/System.Transactions.Local/src/Resources/Strings.resx b/src/libraries/System.Transactions.Local/src/Resources/Strings.resx
index 2acf86bfbbbe07..0548f788a010f4 100644
--- a/src/libraries/System.Transactions.Local/src/Resources/Strings.resx
+++ b/src/libraries/System.Transactions.Local/src/Resources/Strings.resx
@@ -420,7 +420,10 @@
   <data name="TraceSourceBase" xml:space="preserve">
     <value>[Base]</value>
   </data>
-  <data name="DistributedNotSupportOn32Bits" xml:space="preserve">
+  <data name="DistributedNotSupportedOn32Bits" xml:space="preserve">
     <value>Distributed transactions are currently unsupported in 32-bit processes.</value>
   </data>
-</root>
\ No newline at end of file
+  <data name="DistributedNotSupportedOnArm" xml:space="preserve">
+    <value>Distributed transactions are currently unsupported on ARM.</value>
+  </data>
+</root>
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/IPrepareInfo.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/IPrepareInfo.cs
index 0b6c1158f59b31..576f55f66d6a41 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/IPrepareInfo.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/IPrepareInfo.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/IResourceManagerFactory2.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/IResourceManagerFactory2.cs
index b788a17032a5de..dd4777c5445942 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/IResourceManagerFactory2.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/IResourceManagerFactory2.cs
@@ -10,15 +10,15 @@ namespace System.Transactions.DtcProxyShim.DtcInterfaces;
 internal interface IResourceManagerFactory2
 {
     internal void Create(
-        Guid pguidRM,
+        in Guid pguidRM,
         [MarshalAs(UnmanagedType.LPStr)] string pszRMName,
         [MarshalAs(UnmanagedType.Interface)] IResourceManagerSink pIResMgrSink,
         [MarshalAs(UnmanagedType.Interface)] out IResourceManager rm);
 
     internal void CreateEx(
-        Guid pguidRM,
+        in Guid pguidRM,
         [MarshalAs(UnmanagedType.LPStr)] string pszRMName,
         [MarshalAs(UnmanagedType.Interface)] IResourceManagerSink pIResMgrSink,
-        Guid riidRequested,
+        in Guid riidRequested,
         [MarshalAs(UnmanagedType.Interface)] out object rm);
 }
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransaction.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransaction.cs
index a06acb7668a582..de54474609e95b 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransaction.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransaction.cs
@@ -1,9 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
-using System.Transactions.Oletx;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
 
@@ -12,7 +10,7 @@ namespace System.Transactions.DtcProxyShim.DtcInterfaces;
 internal interface ITransaction
 {
     void Commit(
-        [MarshalAs(UnmanagedType.Bool)] bool fRetainingt,
+        [MarshalAs(UnmanagedType.Bool)] bool fRetaining,
         [MarshalAs(UnmanagedType.U4)] OletxXacttc grfTC,
         uint grfRM);
 
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionCloner.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionCloner.cs
index 731e72214f45a5..3090333223c951 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionCloner.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionCloner.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionDispenser.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionDispenser.cs
index c45ea2c5f11631..d5ca43615067fc 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionDispenser.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionDispenser.cs
@@ -7,7 +7,7 @@
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
 
-// https://docs.microsoft.com/previous-versions/windows/desktop/ms679525(v=vs.85)
+// https://docs.microsoft.com/previous-versions/windows/desktop/ms687604(v=vs.85)
 [ComImport, Guid(Guids.IID_ITransactionDispenser), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
 internal interface ITransactionDispenser
 {
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionEnlistmentAsync.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionEnlistmentAsync.cs
index da738568efd5ec..8fb42b4abf8b51 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionEnlistmentAsync.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionEnlistmentAsync.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionExport.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionExport.cs
index 02f64369697ae8..75b6e7ee935220 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionExport.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionExport.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionExportFactory.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionExportFactory.cs
index b82c8f5ebac37f..0369283f3eb181 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionExportFactory.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionExportFactory.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionImport.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionImport.cs
index 310f7d98a54eb7..a7095a6e0237dd 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionImport.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionImport.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
@@ -13,6 +12,6 @@ internal interface ITransactionImport
     void Import(
         uint cbTransactionCookie,
         [MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 0)] byte[] rgbTransactionCookie,
-        Guid piid,
+        in Guid piid,
         [MarshalAs(UnmanagedType.Interface)] out object ppvTransaction);
 }
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionOptions.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionOptions.cs
index 645b4cbcf98b33..66358613be5f5c 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionOptions.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionOptions.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionOutcomeEvents.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionOutcomeEvents.cs
index d0cabc4d708311..362773036f69ca 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionOutcomeEvents.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionOutcomeEvents.cs
@@ -10,11 +10,21 @@ namespace System.Transactions.DtcProxyShim.DtcInterfaces;
 [ComImport, Guid("3A6AD9E2-23B9-11cf-AD60-00AA00A74CCD"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
 internal interface ITransactionOutcomeEvents
 {
-    void Committed([MarshalAs(UnmanagedType.Bool)] bool fRetaining, IntPtr pNewUOW /* always null? */, int hresult);
+    void Committed(
+        [MarshalAs(UnmanagedType.Bool)] bool fRetaining,
+        IntPtr pNewUOW,
+        int hresult);
 
-    void Aborted(IntPtr pboidReason, [MarshalAs(UnmanagedType.Bool)] bool fRetaining, IntPtr pNewUOW, int hresult);
+    void Aborted(
+        IntPtr pboidReason,
+        [MarshalAs(UnmanagedType.Bool)] bool fRetaining,
+        IntPtr pNewUOW,
+        int hresult);
 
-    void HeuristicDecision([MarshalAs(UnmanagedType.U4)] OletxTransactionHeuristic dwDecision, IntPtr pboidReason, int hresult);
+    void HeuristicDecision(
+        [MarshalAs(UnmanagedType.U4)] OletxTransactionHeuristic dwDecision,
+        IntPtr pboidReason,
+        int hresult);
 
     void Indoubt();
 }
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionReceiver.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionReceiver.cs
index ec66d1cab704da..1b1f3886f349fe 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionReceiver.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionReceiver.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionReceiverFactory.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionReceiverFactory.cs
index 30f957cd7f92cf..8a29e9989c89c3 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionReceiverFactory.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionReceiverFactory.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionResourceAsync.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionResourceAsync.cs
index fec5d00462c2dd..79489c671d14b1 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionResourceAsync.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionResourceAsync.cs
@@ -1,9 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
-using System.Transactions.Oletx;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
 
@@ -19,7 +17,10 @@ void PrepareRequest(
 
     void CommitRequest(OletxXactRm grfRM, IntPtr pNewUOW);
 
-    void AbortRequest(IntPtr pboidReason, [MarshalAs(UnmanagedType.Bool)] bool fRetaining, IntPtr pNewUOW);
+    void AbortRequest(
+        IntPtr pboidReason,
+        [MarshalAs(UnmanagedType.Bool)] bool fRetaining,
+        IntPtr pNewUOW);
 
     void TMDown();
 }
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionTransmitter.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionTransmitter.cs
index c427b9a233023b..e00cba9cd6f404 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionTransmitter.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionTransmitter.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionTransmitterFactory.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionTransmitterFactory.cs
index 73c7fa701ebff8..91797781d679a3 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionTransmitterFactory.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionTransmitterFactory.cs
@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Runtime.InteropServices;
 
 namespace System.Transactions.DtcProxyShim.DtcInterfaces;
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionVoterNotifyAsync2.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionVoterNotifyAsync2.cs
index 2eca4063932b72..9fb0abb54d9caa 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionVoterNotifyAsync2.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcInterfaces/ITransactionVoterNotifyAsync2.cs
@@ -10,11 +10,21 @@ namespace System.Transactions.DtcProxyShim.DtcInterfaces;
 [ComImport, Guid("5433376B-414D-11d3-B206-00C04FC2F3EF"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
 internal interface ITransactionVoterNotifyAsync2
 {
-    void Committed([MarshalAs(UnmanagedType.Bool)] bool fRetaining, IntPtr pNewUOW /* always null? */, uint hresult);
+    void Committed(
+        [MarshalAs(UnmanagedType.Bool)] bool fRetaining,
+        IntPtr pNewUOW,
+        uint hresult);
 
-    void Aborted(IntPtr pboidReason, [MarshalAs(UnmanagedType.Bool)] bool fRetaining, IntPtr pNewUOW, uint hresult);
+    void Aborted(
+        IntPtr pboidReason,
+        [MarshalAs(UnmanagedType.Bool)] bool fRetaining,
+        IntPtr pNewUOW,
+        uint hresult);
 
-    void HeuristicDecision([MarshalAs(UnmanagedType.U4)] OletxTransactionHeuristic dwDecision, IntPtr pboidReason, uint hresult);
+    void HeuristicDecision(
+        [MarshalAs(UnmanagedType.U4)] OletxTransactionHeuristic dwDecision,
+        IntPtr pboidReason,
+        uint hresult);
 
     void Indoubt();
 
diff --git a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcProxyShimFactory.cs b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcProxyShimFactory.cs
index ea7813c43951ba..a80f7fb561cf9e 100644
--- a/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcProxyShimFactory.cs
+++ b/src/libraries/System.Transactions.Local/src/System/Transactions/DtcProxyShim/DtcProxyShimFactory.cs
@@ -55,9 +55,14 @@ public void ConnectToProxy(
         out byte[] whereabouts,
         out ResourceManagerShim resourceManagerShim)
     {
-        if (RuntimeInformation.ProcessArchitecture == Architecture.X86)
+        switch (RuntimeInformation.ProcessArchitecture)
         {
-            throw new PlatformNotSupportedException(SR.DistributedNotSupportOn32Bits);
+            case Architecture.X86:
+                throw new PlatformNotSupportedException(SR.DistributedNotSupportedOn32Bits);
+
+            case Architecture.Armv6: // #74170
+            case Architecture.Arm64:
+                throw new PlatformNotSupportedException(SR.DistributedNotSupportedOnArm);
         }
 
         lock (_proxyInitLock)