Take a look at a specific flavor of 1085 event, and its equivalent on Vista/2008, event 7016. The 1085 would show up in the Application log on XP/2003. The 7016 would show up in the Group Policy operational log on Vista/2008 (Event ViewerApplications and Services LogsMicrosoftWindowsGroup PolicyOperational).
Event Type: Error
Event Source: Userenv
Event Category: None
Event ID: 1085
Time: 11:03:23 AM
User: NT AUTHORITYSYSTEM
The Group Policy client-side extension Internet Explorer Zonemapping failed to execute. Please look for any errors reported earlier by that extension.
The 1085 event doesn’t give us the error code. In Vista/2008, the error code shows up on the Details tab of the 7016 event. To view the error code on XP/2003, we need to enable Userenv logging (KB article 221833). Once you’ve enabled Userenv logging and run gpupdate /force, take a look at the %windir%debugusermodeuserenv.log.