Outlook Diary update

Hi vcbertie,

I'm sorry to hear about the issues you're facing with your Outlook calendar. Let's address them step by step.

Retrieving your calendar entries:

1. Log in to Outlook Web App (OWA) and check if the missing appointments are visible there.
2. If the appointments are in OWA but not in the Outlook client, disable cache mode to see if they appear.
3. If appointments are not in OWA either, check the Deleted Items and Recover Deleted Items folders for potential recovery.
4. If appointments are still missing, contact your Office 365 admins to verify if a retention policy deleted them.
   
   Outlook Calendar - diary is missing - Microsoft Community

Reverting to the old version of Outlook:

1. To switch back to the classic version, turn off the "New Outlook" toggle.
2. If the toggle is unavailable, run the old version of Outlook directly from the installation directory.
3. If running the old version opens the new one, either uninstall Outlook or modify the registry setting for UseNewOutlook.

Switch from 'new' Outlook (2023) to 'classic' outlook - Microsoft Community