1. Select your Inbox
  2. From the Menu bar select Folder
  3. Select IMAP folders
  4. Click on Query
  5. Select all IMAP folders
  6. Click on Unsubscribe. You might get a warning some folder are special, Click on OK
  7. Close and reopen Outlook
  8. Select your Inbox
  9. Select again Folder then IMAP folders
  10. Click Query
  11. Click Subscribe
  12. Uncheck show only subscriber folders
  13. Click OK
  14. Outlook will now sync all folders, which can take some time depending on the size of the folders