Using Classic Outlook on Windows for personal email, calendar, and contact management
Hi, are you using Classic Outlook on Windows and did this start after a restart or update?
This usually happens when the Folder Pane is minimized or the view is reset. Open Outlook, go to View, then Folder Pane, and select Normal. If folders still do not show, go to View, then Reset View. Also check if you are in a filtered view by selecting View, then Change View, and choose IMAP Messages or Compact. If using an IMAP account, expand the account name and click More under the folder list, then choose Query to refresh the folder subscription list.