Using a group policy to deploy software is a god send to those who administer larger Active Directory domains. Imagine having to run around to 100 PC's to install a program, then do it again to update the program, then at least one more time to uninstall it. You won't even get me to do that with 5 PC's if I can use a GPO.

While using a group policy to deploy your applications is great, occasionally problems can occur on specific clients. Troubleshooting these "bad" clients can be difficult, but one thing that can help is Application Management Debugging. There is a little known registry entry you can create to turn on Application Management debugging. Once this is enabled the system will create a AppMgmt.log file in %systemroot%\debug\user-mode directory. The information logged here will come in very handy when troubleshooting the client. To enable this we will need to add a new key to the registry. Open regedit and browse to

HKLM\Software\Microsoft\Windows NT\CurrentVersion

Right-click CurrentVersion and create a new key called Diagnostics. Now right-click Diagnostics and create a new REG_DWORD and name it AppMgmtDebugLevel and set the value to 4b.

You will need to reboot if the application has been assigned to the computer, however if it has been assigned (or published) to the user a simple log off/on will suffice. You can now check the AppMgmt.log to determine what is causing the problem. If the AppMgmt.log file is not created it means the policy is not even trying to be applied. This means the policy does not apply to the client, the policy is disabled, or it could be filtered with security settings, or inheritance is blocked. Once you have diagnosed and corrected the problem it is good practice to delete the key. No need taking up valuable disk space with logs you will never read.