You can try renaming the current archive folder (it worked for me, once) but if that fails, you’ll need to delete the current folder. It takes about 15 minutes for the folder change to sync back to the server. The fastest way to open the folder where your Outlook Data File (.pst and.ost. Also, some organizations allow you to export or archive your items to a.pst file.
See the Outlook Data Files (.ost) section for more information.
To use Cached Exchange Mode or to work offline, copies of your items are saved in an offline Outlook Data File (.ost).
