Use the When to Stop dialog to specify a maximum number of minutes for the policy to run. Once this time limit is reached the policy stops searching for messages. Messages already selected for archiving continue to be archived, but no new ones are found. If the policy is restarted immediately, it runs from the beginning again, but should process quickly up to the point it started the last time it stopped, since there should be very few messages to archive.
This option does not affect the processing of PST folders: