Access Is Denied in WTSQueryUserToken and Windows 2003 Ent SP1

[Sendare]

Hello,
I have a service that needs to get the current user's token. I do this by using the HandlerEx along with the WTS notifications that occur during any Logon/Logoff/Lock/etc.. to get the SessionId and call WTSQueryUserToken with that SessionId. This code works fine on the XP Sp1 and Sp2 operating systems, but for some reason, whenever I call it with Windows 2003 enterprise SP1, the code fails to run, returning an error of Access Is Denied.

I looked it up and saw that Access Is Denied means that I either don't have the Local System user or the SE_TCB_NAME privilege enabled. I have both of them enabled, and it still doesn't work.

I'm really lost, can anyone please help?
Thanks

[Mihai Greavu]

Hello,
After installing the service check that it actually runs in the context of the LocalSystem account (it's not enough to just have the LocalSystem account present)
In services.msc->Properties->Log On Tab->Log on as.
If yes, check that LocalSystem account has all the privileges required by WTSQueryUserToken() enabled.