You can use both, though rarely needed:
It forces the client to re-evaluate and re-apply every applicable GPO, regardless of whether the version number in the SYSVOL folder has changed. When to use it: gpupdate /sync vs /force
It tells the client to re-process every applicable Group Policy Object (GPO), regardless of whether the GPO has changed since the last cycle. You can use both, though rarely needed: It
gpupdate /force → Stops current Group Policy client → Re-downloads all GPOs (no delta detection) → Overwrites all managed settings → Restarts the policy engine → Returns after foreground apply finishes /force bypasses this check
Normally, the client only processes GPOs with a new version number. /force bypasses this check. However, even with /force , it will still skip "foreground" policies if they require a logout or reboot to take effect. It simply ensures that every registry-based setting is rewritten. gpupdate /sync: The Forensic Synchronization
Overkill. A normal gpupdate reapplies only changed policies. /force reapplies – unnecessary in 95% of cases.
gpupdate /force /sync