Hi all, I've added a manifest file to my VS Project and set the requested execution level to "require administrator" <requestedExecutionLevel level="requireAdministrator" uiAccess="false" /> Furthermore I've already signed my application successful (Signtool.exe). If I try to start my application, the UAC pupup will occur and shows me that "Application xyz" wasn't signed by a "known publisher" --> unknown publisher. Very strange. But after I perform the following steps it will work fine: - Right click application --> Properties --> Digital Signatures --> select my certificate --> click Details This digital signature is OK. Ok, now close all windows and restart application --> it (UAC) display my name as a trusted publisher. Can someone explain that strange behaviour, please? I can not perform these steps in our hole IT environment (thousands of server / clients). Thanks

Hi Paul, thanks for your fast answer. ~ You need to look at the Trusted Publishers store and Group Policy ~ I am familar with the trusted publishers store and group policy settings. This has nothing to do with my problem. --> e.g. company XYZ sell their signed application, the publishers certificate isn't located in trusted publishers store but works like a charm (UAC -> known publisher company XYZ) ~ Note that since your question is development related, you're likely better off posting to one of the MSDN forums, rather than here. ~ You are right Paul, sorry.