CoCreateInstance and CoCreateInstanceEx are not valid APIs for Windows 8 Store or Windows Universal apps, and it's use will fail WACK.
Instead you use CoCreateInstanceFromApp which is allowed by WACK. To simplify coding, there's an automatic conversion in the headers if you are building with the correct headers, toolset, and WINAPI_FAMILY partition:
// combaseapi.h
#if WINAPI_PARTITION_APP && !WINAPI_PARTITION_DESKTOP
__inline _Check_return_ HRESULT CoCreateInstance(
_In_ REFCLSID rclsid,
_In_opt_ LPUNKNOWN pUnkOuter,
_In_ DWORD dwClsContext,
_In_ REFIID riid,
_COM_Outptr_ _At_(*ppv, _Post_readable_size_(_Inexpressible_(varies))) LPVOID FAR* ppv)
{
MULTI_QI OneQI;
HRESULT hr;
OneQI.pItf = NULL;
#ifdef __cplusplus
OneQI.pIID = &riid;
#else
OneQI.pIID = riid;
#endif
hr = CoCreateInstanceFromApp( rclsid, pUnkOuter, dwClsContext, NULL, 1, &OneQI );
#ifdef _PREFAST_
if (SUCCEEDED(hr) && SUCCEEDED(OneQI.hr))
_Analysis_assume_(OneQI.pItf != NULL);
else
_Analysis_assume_(OneQI.pItf = NULL);
#endif
*ppv = OneQI.pItf;
return FAILED(hr) ? hr : OneQI.hr;
}
__inline _Check_return_ HRESULT CoCreateInstanceEx(
_In_ REFCLSID Clsid,
_In_opt_ IUnknown * punkOuter,
_In_ DWORD dwClsCtx,
_In_opt_ COSERVERINFO * pServerInfo,
_In_ DWORD dwCount,
_Inout_updates_(dwCount) MULTI_QI *pResults )
{
return CoCreateInstanceFromApp(Clsid, punkOuter, dwClsCtx, pServerInfo, dwCount, pResults);
}
#endif // WINAPI_PARTITION_APP && !WINAPI_PARTITION_DESKTOP
#pragma endregion
If the library you are using is actually calling CoCreateInstance, it will not pass WACK for the Windows Store. They need to rebuild the library to comply with the WINAPI_FAMILY for UWP.
