diff --git a/lib/private/Encryption/DecryptAll.php b/lib/private/Encryption/DecryptAll.php
index 34a3e1bff911..376cdd3d5aa9 100644
--- a/lib/private/Encryption/DecryptAll.php
+++ b/lib/private/Encryption/DecryptAll.php
@@ -206,6 +206,10 @@ protected function decryptUsersFiles($uid, ProgressBar $progress, $userCount) {
 		while ($root = array_pop($directories)) {
 			$content = $this->rootView->getDirectoryContent($root);
 			foreach ($content as $file) {
+				// only decrypt files owned by the user
+				if($file->getStorage()->instanceOfStorage('OC\Files\Storage\Shared')) {
+						continue;
+				}
 				$path = $root . '/' . $file['name'];
 				if ($this->rootView->is_dir($path)) {
 					$directories[] = $path;
diff --git a/tests/lib/Encryption/DecryptAllTest.php b/tests/lib/Encryption/DecryptAllTest.php
index d7cf2fb7baf7..3f7cb59c8f48 100644
--- a/tests/lib/Encryption/DecryptAllTest.php
+++ b/tests/lib/Encryption/DecryptAllTest.php
@@ -239,6 +239,10 @@ public function dataTestDecryptAllUsersFiles() {
 	}
 
 	public function testDecryptUsersFiles() {
+		$storage = $this->getMockBuilder('OC\Files\Storage\Shared')
+			->disableOriginalConstructor()
+			->getMock();
+
 		/** @var DecryptAll | \PHPUnit_Framework_MockObject_MockObject  $instance */
 		$instance = $this->getMockBuilder('OC\Encryption\DecryptAll')
 			->setConstructorArgs(
@@ -254,15 +258,15 @@ public function testDecryptUsersFiles() {
 		$this->view->expects($this->at(0))->method('getDirectoryContent')
 			->with('/user1/files')->willReturn(
 				[
-					new FileInfo('path', null, 'intPath', ['name' => 'foo', 'type'=>'dir'], null),
-					new FileInfo('path', null, 'intPath', ['name' => 'bar', 'type'=>'file', 'encrypted'=>true], null)
+					new FileInfo('path', $storage, 'intPath', ['name' => 'foo', 'type'=>'dir'], null),
+					new FileInfo('path', $storage, 'intPath', ['name' => 'bar', 'type'=>'file', 'encrypted'=>true], null)
 				]
 			);
 
 		$this->view->expects($this->at(3))->method('getDirectoryContent')
 			->with('/user1/files/foo')->willReturn(
 				[
-					new FileInfo('path', null, 'intPath', ['name' => 'subfile', 'type'=>'file', 'encrypted'=>true], null)
+					new FileInfo('path', $storage, 'intPath', ['name' => 'subfile', 'type'=>'file', 'encrypted'=>true], null)
 				]
 			);