Does the Outlook add-on have to be installed for archiving to work on a users mailbox ? I've gotten a couple of conflicting answers to this. I wonder because I have a user that I haven't installed the add-on for who looks to have about 4,000 items ready for archiving but after 5 days only 330 are showing as archived ? If the client add-on has to be installed then I'd expect to see zero items archived. All the logs are clear and the other mailboxes are working as intended, the absence of the add-on is the only obvious difference.