If Outlook stops responding at the "Processing" page, you can close it, start it in safe mode, then close and open it normally to resolve the issue of why won't Outlook open, follow these instructions Outlook should be closed. Choose one of the following choices to start Outlook in safe mode. Choose Start, type Outlook.exe /safe, and press Enter on Windows 10. In Windows 7, go to Start and type Outlook /safe in the Search programmes and files box, then click Enter. Choose Run from the Apps menu in Windows 8, type Outlook /safe, and then select OK. Close Outlook and reopen it as usual.
