Using Classic Outlook on Windows for personal email, calendar, and contact management
Reset the Office cache, it should fix the problem:
- Close Outlook
- Rename or Remove these two folders: %LOCALAPPDATA%\Microsoft\Office\16.0\wef %userprofile%\AppData\Local\Microsoft\Outlook\HubAppFileCache
Re-open Outlook and click the "To-Do" shortcut, and it should open without issue.
THANK YOU! This worked perfectly!