Outlook Issues

If you still can't switch back:
You might need to manually disable the new Outlook:
Open Registry Editor: Search for "Registry Editor" in the Windows Start Menu and open it.

Navigate to the correct path: Go to Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences.
Find and modify "UseNewOutlook": Look for the "UseNewOutlook" setting and double-click on it.
Change the Value Data: Set the Value Data to 0 and click "OK".
Try launching classic Outlook again: This should revert to the classic version.