Behavioral change when using WMI-Filter in a GPO
When using GPO and WMI-Filters you may experience long startup times when you are using WMI Queries. This can occur if the WMI queries in question are taking an extended amount of time to finish.
There is no timeout for this functionality in Windows XP, so startup may be prolonged by the amount of time the query takes.
In Windows Vista and newer this behavior has been changed and now includes a hardcoded timeout of 30 seconds. If this timeout is reached, the query is automatically treated as false regardless of the eventual return value.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB2587435.