Background Refresh of Group Policy
In addition to the initial processing of Group Policy when the computer starts and when the user logs on (also referred to as foreground policy application) the system periodically applies (refreshes) Group Policy in the background. During a refresh, policy settings are applied asynchronously.
By default, a refresh occurs every 90 minutes. The system may add a random time of up to 30 minutes to the refresh interval. You can change these default values by using a Group Policy setting in the Administrative Templates extension to Group Policy. Setting the value to zero minutes causes the refresh rate to be set to seven seconds.
Not all Group Policy extensions are processed during a background refresh. Folder redirection processing occurs only when a user logs on, and the processing of software installation policy occurs only when a computer starts and when a user logs on.
Caution Periodic processing of these policies could cause undesirable results. For example, during software installation, an error would occur if the system tried to uninstall or upgrade an application currently running on a client computer.
Be aware that even though the system processes the Scripts extension to Group Policy during a background refresh, the individual scripts run only when the computer starts and shuts down, and when a user logs on and logs off.
During a policy refresh, by default, a client-side extension reapplies policy settings only if it detects a change to one of its GPOs or to its list of GPOs. This is for performance reasons.
Administrators can refresh policy on demand using the Gpupdate.exe command line utility, but servers cannot request an on-demand application of Group Policy by a client.
Applications can request a policy refresh by calling the RefreshPolicy function.
For more information, see the following topic: