outlook not starting

https://support.office.com/en-us/article/Outlook-not-responding-stuck-at-Processing-stopped-working-freezes-or-hangs-5c313d04-64af-4441-82d2-44e5a43eee5a

Start Outlook in safe mode to fix "Processing" screen

If Outlook stops responding at a screen that says "Processing," you can close Outlook, start it in safe mode, then close it and open it normally to fix the problem.

Close Outlook.

Launch Outlook in safe mode by choosing one of the following options.

In Windows 10, choose Start, type Outlook.exe /safe, and press Enter.

In Windows 7, choose Start, and in the Search programs and files box, type Outlook /safe, and then press Enter.

In Windows 8, on the Apps menu, choose Run, type Outlook /safe, and then choose OK.

Close Outlook, and then open it normally.