Yesterday, I found my Outlook is not working anymore. I cannot open it! It stayed in a splash screen,the "processing..." wordings is staying in there. After I did some researches and testing, I found the root cause is from the COM Add-ins for Outlook. To solve this problem, you need to go into the safe mode of outlook, you just need to type "outlook /safe" in "Run...." or command prompt. After you enter safe mode, you need to File->Options->Add-ins->COM-Add-ins->Go

Then you checked all add-ins you do not need to use. Finally, you close your outlook, open it in normal mode again. It will work again.