APPLICATION COMPATIBILITY - USER ACCOUNT CONTROL (UAC)
Description: User Account Control (UAC) is the functionality within Windows Vista that allows a user to run under a safer, less privileged context, but switch to an Administrator context when needed. Under normal circumstances, every user on Windows Vista will run with UAC enabled, which means they are running under a standard user security token. If administrative rights are needed, an Administrator security token is used for that action only.
Scoping the Issue: The first thing to determine is if the issue you are seeing is related to UAC or not. Some applications require Administrator privileges to run and will not run for a normal user. The way to test if this is the case is to simply right-click the application or shortcut and choose Run as Administrator. If the application then works, it means that the app is not compatible with UAC without intervention.
Data Gathering: In all instances, collecting either MPS Reports with the General, Internet and Networking, Business Networks and Server Components diagnostics, or a Performance-oriented MSDT manifest must be done. For UAC group policy settings, please review all entries starting with 'User Account Control' within the following location in Gpedit.msc: Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options
Troubleshooting / Resolution: The best way to determine if UAC is related to the problem symptom is to simply disable it as a test. This can be done via Msconfig.exe on the Tools tab. Running without UAC is not recommended except as a test. If it is determined that the problem is related to UAC, then Developer Support will need to be engaged if you (or your application vendor) require assistance with re-coding the application to be UAC-compatible.
Additional Resources:
Microsoft