Hi,
The "Group Policy Refresh Interval" is an Interval, not an hour.
It is the number of minutes of waiting before a computer re-check GPO status and re-apply them if changes have occured on GPOs since the last time GPOs have been checked.
By default, for member computers, the re-check interval is 90 minutes (plus a random offset to load balance re-checks in the time). That mean that every computer will ask a DC for any GPO change every 90 minutes. If no change has occured on GPO the computer DO NOT reapply current GPOs at this time.
There is another interval that you can configure for "re-apply". By default this interval is 1440 minutes that is 24 hours. That means that even if GPOs have not changed on the domain every member computer will re-apply the GPO at least every 24 hours since the last reapplying.
So if you start your computer at 9:30 in the morning, it will apply GPOs at startup. Then around 11:00 it will check for GPO changes on the domain. If no GPO change have been made nothing happens on the computer. The computer will then re-check for GPO changes around 12:30, then at 2:00 PM, then at 3:30 PM, etc...
If you let your computer switched on, the next day at 9:30 in the morning the computer will reapply all GPOs even if no change have occured.
What is important to remember is that some part of GPOs can ONLY be applied at startup. As an example "Startup Scripts" will only be executed when the computer is started and will never be re-applied every 24 hours...
If you want all your computers to reapply GPOs at a precise time you'll have to create a scheduled task on every computer to launch the GPUPDATE /FORCE command. But be careful: if all your computers ask for GPO applying all together at the same time your DCs will probably be overloaded !
Have a good day.
