Sometimes there are errors in the event log on clients or servers that indicate faulty group policies (GPOs). Unfortunately, only the ID of the GPO is displayed in the event log, so it can take some time to search for the corresponding GPO:
You can make your work easier with PowerShell and the ActiveDirectory PowerShell SnapIns
get-gpo -all | where {$_.id -match "XXXXXXX-XXXX-XXXX-XXXX-B026-925CC1643B3X"}
This at least saves you having to search for the problematic GPO.