When you make a change to a Group Policy Object (GPO), the change takes place on a Windows 2000 domain controller. The change is replicated to all other domain controllers in the Active Directory. All Windows computers in the Active Directory check for modifications to GPOs at regular intervals. If they find changes, they apply them during the next interval.
If you need to apply the change immediately, you can use the following command to trigger the updating process:
gpupdate /force
This command compares the currently applied GPO to the GPO that is located on the domain controllers. If nothing has changed since the last time the GPO was applied, then the GPO is skipped.
If Windows accepts the request, it will display the following message:
Updating Policy... User Policy update has completed successfully. Computer Policy update has completed successfully.