diff --git a/build/VStudio/testing/mirror.vcxproj b/build/VStudio/testing/mirror.vcxproj
index a0e5a2f0..62a93367 100644
--- a/build/VStudio/testing/mirror.vcxproj
+++ b/build/VStudio/testing/mirror.vcxproj
@@ -102,6 +102,7 @@
       <PreprocessorDefinitions>WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\..\src;..\..\..\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -117,6 +118,7 @@
       <PreprocessorDefinitions>_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\..\src;..\..\..\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -134,6 +136,7 @@
       <PreprocessorDefinitions>WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\..\src;..\..\..\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -153,6 +156,7 @@
       <PreprocessorDefinitions>NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\..\src;..\..\..\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
diff --git a/build/VStudio/testing/winfsp-tests.vcxproj b/build/VStudio/testing/winfsp-tests.vcxproj
index 5908c755..28439205 100644
--- a/build/VStudio/testing/winfsp-tests.vcxproj
+++ b/build/VStudio/testing/winfsp-tests.vcxproj
@@ -102,6 +102,7 @@
       <PreprocessorDefinitions>__func__=__FUNCTION__;WIN32;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\..\src;..\..\..\inc;..\..\..\ext</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -117,6 +118,7 @@
       <PreprocessorDefinitions>__func__=__FUNCTION__;_DEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\..\src;..\..\..\inc;..\..\..\ext</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -134,6 +136,7 @@
       <PreprocessorDefinitions>__func__=__FUNCTION__;WIN32;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\..\src;..\..\..\inc;..\..\..\ext</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -153,6 +156,7 @@
       <PreprocessorDefinitions>__func__=__FUNCTION__;NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\..\src;..\..\..\inc;..\..\..\ext</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
diff --git a/build/VStudio/winfsp_dll.vcxproj b/build/VStudio/winfsp_dll.vcxproj
index 2bdac853..63313dbc 100644
--- a/build/VStudio/winfsp_dll.vcxproj
+++ b/build/VStudio/winfsp_dll.vcxproj
@@ -103,6 +103,7 @@
       <PreprocessorDefinitions>WINFSP_DLL_INTERNAL;WIN32;_DEBUG;_WINDOWS;_USRDLL;WINFSPDLL_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\src;..\..\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
@@ -118,6 +119,7 @@
       <PreprocessorDefinitions>WINFSP_DLL_INTERNAL;_DEBUG;_WINDOWS;_USRDLL;WINFSPDLL_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\src;..\..\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
@@ -135,6 +137,7 @@
       <PreprocessorDefinitions>WINFSP_DLL_INTERNAL;WIN32;NDEBUG;_WINDOWS;_USRDLL;WINFSPDLL_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\src;..\..\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
@@ -154,6 +157,7 @@
       <PreprocessorDefinitions>WINFSP_DLL_INTERNAL;NDEBUG;_WINDOWS;_USRDLL;WINFSPDLL_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>..\..\src;..\..\inc</AdditionalIncludeDirectories>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
diff --git a/src/sys/device.c b/src/sys/device.c
index 67cf6f94..22f9b8cd 100644
--- a/src/sys/device.c
+++ b/src/sys/device.c
@@ -213,7 +213,7 @@ BOOLEAN FspDeviceRetain(PDEVICE_OBJECT DeviceObject)
     DeviceExtension = FspDeviceExtension(DeviceObject);
     KeAcquireSpinLock(&DeviceExtension->SpinLock, &Irql);
     Result = 0 != DeviceExtension->RefCount;
-    if (!Result)
+    if (Result)
         DeviceExtension->RefCount++;
     KeReleaseSpinLock(&DeviceExtension->SpinLock, Irql);
 
diff --git a/src/sys/fsctl.c b/src/sys/fsctl.c
index 23a67c6e..8e956d7b 100644
--- a/src/sys/fsctl.c
+++ b/src/sys/fsctl.c
@@ -108,8 +108,8 @@ static NTSTATUS FspFsctlCreateVolume(
     PVOID SystemBuffer = Irp->AssociatedIrp.SystemBuffer;
     const FSP_FSCTL_VOLUME_PARAMS *Params = SystemBuffer;
     PSECURITY_DESCRIPTOR SecurityDescriptor = (PVOID)((PUINT8)Params + FSP_FSCTL_VOLUME_PARAMS_SIZE);
-    DWORD SecurityDescriptorSize = InputBufferLength - sizeof *Params;
-    if (sizeof *Params >= InputBufferLength || 0 == SystemBuffer ||
+    DWORD SecurityDescriptorSize = InputBufferLength - FSP_FSCTL_VOLUME_PARAMS_SIZE;
+    if (FSP_FSCTL_VOLUME_PARAMS_SIZE >= InputBufferLength || 0 == SystemBuffer ||
         !FspValidRelativeSecurityDescriptor(SecurityDescriptor, SecurityDescriptorSize,
             OWNER_SECURITY_INFORMATION | DACL_SECURITY_INFORMATION))
         return STATUS_INVALID_PARAMETER;
@@ -475,11 +475,11 @@ NTSTATUS FspFileSystemControl(
     switch (FspDeviceExtension(DeviceObject)->Kind)
     {
     case FspFsvolDeviceExtensionKind:
-        FSP_RETURN(Result = FspFsctlFileSystemControl(DeviceObject, Irp, IrpSp));
+        FSP_RETURN(Result = FspFsvolFileSystemControl(DeviceObject, Irp, IrpSp));
     case FspFsvrtDeviceExtensionKind:
         FSP_RETURN(Result = FspFsvrtFileSystemControl(DeviceObject, Irp, IrpSp));
     case FspFsctlDeviceExtensionKind:
-        FSP_RETURN(Result = FspFsvolFileSystemControl(DeviceObject, Irp, IrpSp));
+        FSP_RETURN(Result = FspFsctlFileSystemControl(DeviceObject, Irp, IrpSp));
     default:
         FSP_RETURN(Result = STATUS_INVALID_DEVICE_REQUEST);
     }