CreateProcessAsUser() not working - c++

Question

I am trying to start GUI application using my service. I developed the service on VS2012 and running on windows 7. But CreateProcessAsUser function doesn't start application even though it returns successfully. following is my code:
PHANDLE hToken = NULL;
WTSQueryUserToken (WTSGetActiveConsoleSessionId (), hToken) ;
if( !CreateProcessAsUser( hToken,
NULL, // No module name (use command line)
pPath, // Command line
NULL, // Process handle not inheritable
NULL, // Thread handle not inheritable
FALSE, // Set handle inheritance to FALSE
0, // No creation flags
NULL, // Use parent's environment block
NULL, // Use parent's starting directory
&si, // Pointer to STARTUPINFO structure
&pi ) // Pointer to PROCESS_INFORMATION structure
)
what could be the issue?
Thanks,
KM.

Answer 1

After retrieving the user token from WTSQueryUserToken(), call DuplicateTokenEx() to convert it into a primary token, and pass that token to CreateProcessAsUser(). You also need to specify the "winsta0\default" (use: "winsta0\\default") desktop via the STARTUPINFO structure. You should also call CreateEnvironmentBlock() using the same token, and pass that environment to CreateProcessAsUser() as well.

Answer 2

There is not enough information to be sure of my answer but that kind of error often happen when the structures are not correctly initialized.
PHANDLE hToken = NULL;
WTSQueryUserToken (WTSGetActiveConsoleSessionId (), hToken) ;
//be sure that the handle is correct ! (can be the issue)
if (!hToken) printf("Token error.\n");
//init here !
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
ZeroMemory(&pi, sizeof(pi));
if( !CreateProcessAsUser( hToken,
NULL, // No module name (use command line)
pPath, // Command line
NULL, // Process handle not inheritable
NULL, // Thread handle not inheritable
FALSE, // Set handle inheritance to FALSE
0, // No creation flags
NULL, // Use parent's environment block
NULL, // Use parent's starting directory
&si, // Pointer to STARTUPINFO structure
&pi ) // Pointer to PROCESS_INFORMATION structure
)

Answer 3

I faced a similar issue while using WTSQueryUserToken in windows 7, but the same function worked in windows 10.
So I took the explorer.exe token, called the DuplicateTokenEx function.
Set the corresponding values for startupinfo structure
si.lpDesktop = "winsta0\\default";
si.wShowWindow = SW_SHOWNORMAL;
si.dwFlags = STARTF_USESHOWWINDOW;
and called createprocessasuser