Outlook runs only in Safe mode

If Outlook will run only in Safe mode, check the Outlook Add-ins.  Anti-virus and other add-ins can sometimes cause Outlook to stop responding, freeze or crash. Search for Add-ins in Outlook Help to find the steps to disable add-ins for your particular version of Outlook.  Start by disabling all non-Microsoft Add-ins and see if Outlook will then start and run normally. If it will, then you can enable Add-ins again one at a time until you find the one causing the trouble.

Another possible cause of Outlook problems is a Personal Folders File (PST) that is corrupt or very large.  You can check for corruption of the file by running the Microsoft Inbox Repair Tool Scanpst.exe.  This link tells you where to find it and how to use it.