Too Many GPOs
The Group Policy service, during the preprocessing phase, ensures that Group Policy is not configured beyond the scope of the service. An improper configuration could prevent Group Policy from applying to a computer or user.
Reduce excessive numbers of linked Group Policy objects
Group Policy objects can be linked throughout the Active Directory hierarchy. Windows traverse this hierarchy, searching for Group Policy objects that apply to the user or computer. Windows cannot apply more than 999 Group Policy objects to a single user or computer.
To reduce excessive numbers of linked Group Policy objects (GPOs):
Determine the total number of Group Policy objects (GPOs) within the scope of the user or computer. You can do this using the Group Policy Results reporting feature from the Group Policy Management Console (GPMC). Expand the Group Policy Objects section in the report to view the list of applied and denied Group Policy objects.
Determine the number of GPOs you must remove from the scope of the computer or user to fall under the limit of 999. This is the number of GPOs you must remove from the scope of the computer or user.
Analyze each of the policy settings to determine if the computer or user is receiving any GPOs with duplicate settings. You can do this by using the reporting features in GPMC.
Perform one or more of the following actions to remove the GPO from the scope of the user:
Unlink the GPO from the site, domain, or organizational unit. This removes the GPO from the scope of all users within the site, domain, or organizational unit, respectively.
Move the computer or user to a different organizational unit where fewer GPOs are linked. Or consider moving the computer or user to a higher location in the Active Directory hierarchy.
Use security filtering to prevent the GPO from being in scope with the computer or user.