diff --git a/src/c/CudaMex.vcxproj b/src/c/CudaMex.vcxproj
index 055f13c4684f81f09ffe4484e03568c8ec896f12..9a47f8b5f388e9949907cacda34f0b0c54030847 100644
--- a/src/c/CudaMex.vcxproj
+++ b/src/c/CudaMex.vcxproj
@@ -55,7 +55,7 @@
       <Optimization>Disabled</Optimization>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>.;$(MATLAB_DIR)\extern\include;external</AdditionalIncludeDirectories>
-      <PreprocessorDefinitions>MEX_BUILD;_WINDLL;USE_PROCESS_MUTEX;_CRT_SECURE_NO_WARNINGS;_CRTDBG_MAP_ALLOC;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>MEX_BUILD;USE_PROCESS_MUTEX;_WINDLL;_CRT_SECURE_NO_WARNINGS;_CRTDBG_MAP_ALLOC;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <PreprocessToFile>false</PreprocessToFile>
     </ClCompile>
     <Link>
@@ -77,7 +77,7 @@ copy $(OutDir)CudaMex.dll "$(ProjectDir)Mex.mexw64"</Command>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <SDLCheck>true</SDLCheck>
       <AdditionalIncludeDirectories>.;$(MATLAB_DIR)\extern\include;external</AdditionalIncludeDirectories>
-      <PreprocessorDefinitions>MEX_BUILD;_WINDLL;_CRT_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>MEX_BUILD;USE_PROCESS_MUTEX;_WINDLL;_CRT_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <PreprocessToFile>false</PreprocessToFile>
     </ClCompile>
     <Link>
diff --git a/src/c/CudaPy3DLL.vcxproj b/src/c/CudaPy3DLL.vcxproj
index 7af4f5aecc0210004c3637a03b3464f3502e3864..695588e6e10a44c3f607ba96419ec9fdb6cff672 100644
--- a/src/c/CudaPy3DLL.vcxproj
+++ b/src/c/CudaPy3DLL.vcxproj
@@ -156,7 +156,7 @@
       </PrecompiledHeader>
       <WarningLevel>Level3</WarningLevel>
       <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>PY_BUILD;WIN32;_DEBUG;_WINDOWS;_USRDLL;CUDAPY3DLL_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>PY_BUILD;USE_PROCESS_MUTEX;WIN32;_DEBUG;_WINDOWS;_USRDLL;CUDAPY3DLL_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>.;external;Python;$(PYTHON3_DIR)/include;$(NUMPY3_DIR)/core/include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessToFile>false</PreprocessToFile>
     </ClCompile>
@@ -192,7 +192,7 @@
       <Optimization>MaxSpeed</Optimization>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
-      <PreprocessorDefinitions>PY_BUILD;WIN32;NDEBUG;_WINDOWS;_USRDLL;CUDAPY3DLL_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>PY_BUILD;USE_PROCESS_MUTEX;WIN32;NDEBUG;_WINDOWS;_USRDLL;CUDAPY3DLL_EXPORTS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <AdditionalIncludeDirectories>.;external;Python;$(PYTHON3_DIR)/include;$(NUMPY3_DIR)/core/include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessToFile>false</PreprocessToFile>
     </ClCompile>
diff --git a/src/c/makefile b/src/c/makefile
index bf141265e9e92cf310d92f0b8d5b04edee621eea..3b5a134db89da61afebd1a1bd8b6feb145c304d7 100755
--- a/src/c/makefile
+++ b/src/c/makefile
@@ -113,19 +113,19 @@ $(OBJ_DIR)/%.o: Cuda/%.cpp
 #########################################
 $(OBJ_DIR)/%.o: Mex/%.cpp
 	@mkdir -p $(@D)
-	$(C_COMPILER) $(GCC_FLAGS) -DMEX_BUILD  $(MEX_INC) -c $< -o $@
+	$(C_COMPILER) $(GCC_FLAGS) -DMEX_BUILD -DUSE_PROCESS_MUTEX $(MEX_INC) -c $< -o $@
 
 $(OBJ_DIR)/Mx%.o: ScriptCmds/%.cpp
 	@mkdir -p $(@D)
-	$(C_COMPILER) $(GCC_FLAGS) -DMEX_BUILD  $(MEX_INC) -c $< -o $@
+	$(C_COMPILER) $(GCC_FLAGS) -DMEX_BUILD -DUSE_PROCESS_MUTEX $(MEX_INC) -c $< -o $@
 
 $(OBJ_DIR)/%.o: Python/%.cpp
 	@mkdir -p $(@D)
-	$(C_COMPILER) $(GCC_FLAGS) -DPY_BUILD  $(PY_INC) -c $< -o $@
+	$(C_COMPILER) $(GCC_FLAGS) -DPY_BUILD -DUSE_PROCESS_MUTEX $(PY_INC) -c $< -o $@
 
 $(OBJ_DIR)/Py%.o: ScriptCmds/%.cpp
 	@mkdir -p $(@D)
-	$(C_COMPILER) $(GCC_FLAGS) -DPY_BUILD  $(PY_INC) -c $< -o $@
+	$(C_COMPILER) $(GCC_FLAGS) -DPY_BUILD -DUSE_PROCESS_MUTEX $(PY_INC) -c $< -o $@
 
 #########################################
 # files to clean up