When I first started learning about Active Directory, Group Policy always seemed very fickle. Sometimes I could run GPUpdate, other times I had to append the /force option.
As it turned out, Group Policy was always working – I just didn’t understand it. So what’s the difference between GPUpdate and GPUpdate /force? Well –
GPUpdate: Applies any policies that is new or modified
GPUpdate /force: Reapplies every policy, new and old.
So which one should I use? 99% of the time, you should only run gpupdate. If you just edited a GPO and want to see results immediately, running gpupdate will do the trick. In fact, running GPUpdate /force on a large number of computers could adversely affect network resources. This is because these machines will hit a domain controller and reevaluate every GPO applicable to them.
Notice the Group Policy Update option for OUs: