We had a problem where policies.user.xml was in the wrong encoding. The STPolicy service did start and seemed to work.
But the Sametime proxy server couldn't authenticate the users anymore. It stopped when polling for user information.
If the STPolicy wasn't started, it was easier to find and pinpoint the problem. Now it took us 2 days scrolling through all verboce traces to find the problem.
One file....just one file.