diff --git a/visualc/VS2010/mbedTLS.vcxproj b/visualc/VS2010/mbedTLS.vcxproj
index e6d6532..da026d9 100644
--- a/visualc/VS2010/mbedTLS.vcxproj
+++ b/visualc/VS2010/mbedTLS.vcxproj
@@ -358,6 +358,7 @@
     <ClCompile Include="..\..\tests\src\helpers.c" />
     <ClCompile Include="..\..\tests\src\psa_crypto_helpers.c" />
     <ClCompile Include="..\..\tests\src\random.c" />
+    <ClCompile Include="..\..\tests\src\threading_helpers.c" />
     <ClCompile Include="..\..\3rdparty\everest\library\everest.c" />
     <ClCompile Include="..\..\3rdparty\everest\library\Hacl_Curve25519_joined.c" />
     <ClCompile Include="..\..\3rdparty\everest\library\x25519.c" />