We discussed the specifics of GPUpdate and the various switches that can be used with it in Chapter 3, Daily Tasks in Group Policy, but it is very important to mention it in this chapter as well, because this is probably the most commonly utilized Group Policy troubleshooting tool. If ever you are in a situation where you believe GPO settings are not making their way down to a user or computer, the very first thing to test is a simple gpupdate /force command, where we can watch in real time as the client workstation attempts to reach out to a Domain Controller and process any Group Policy settings that are waiting for it. Any other troubleshooting would be premature if you have not first attempted to GPUpdate.
If GPUpdate presents you with errors, now you have a defined path for continued troubleshooting. Errors in GPUpdate can point out network connection problems, or permission problems, or even clue you in when a particular policy setting is waiting for a logoff or reboot.
When GPUpdate comes back with a successful status, chances are that Group Policy is processing successfully, and the issue you are tracking is sourced elsewhere. But keep in mind that a restart of the client operating system is never a bad idea. There are some changes, such as moving a computer from one OU to another, that are not immediately recognized by the workstation. Moving a computer to a new OU will often change the GPOs that are being applied to the workstation, but those GPO changes will only happen once the computer knows about the new OU membership. Rebooting is the fastest and easiest way to force a client to recognize new OU or group membership. Group Policy always processes during operating system boot, so doing a quick restart will both ensure that changes inside Active Directory are picked up by the machine, as well as force Group Policy to reprocess and reapply.
"Have you tried rebooting?" is and has always been question numero uno when calling any help desk, with good reason. There are many symptoms inside Windows that are mysteriously fixed after a reboot, and sometimes Group Policy falls into this boat as well. I will say that Windows 10 is far superior to its predecessors. In Windows 10, you really don't have to reboot very often, but when you're working on an issue and trying to determine what's going askew inside GPO-land, falling back on the good ole reboot is never a bad idea.