Outlook 2016 won't go beyond "Processing" Upon Launch

Hi.

Welcome to Microsoft Community.

I would like to know what type of account you have configured in Outlook.  (POP3, IMAP, Exchange ActiveSync or an Exchange account)

How many email address do you have configured in Outlook.

Meanwhile Open the Task manager.  Here’s a tip:  Press CTRL+Shift+ESC at the same time. (on the keyboard)

The task manager windows pops up, click more details, then click on process tab, you see a list of apps running on the computer, let us choose Outlook app and click End.

After which, let us open Outlook in safe mode and check.

To do that, close Outlook. Click on Start – All Programs – Accessories – Run, and in the open box type in Outlook /safe and hit ok. (Note: There is a space between Outlook and /). 

If the application works fine safe mode, try disabling the add ins for the application and check the result,

Click the File tab.

Go to Options.

Click Add-ins.

In the Manage section, select COM Add-ins and click on Go.

Now uncheck the Add-ins and click on OK.

I hope the above suggestion helps. If you need further assistance, get back to us and we will be glad to assist you.

Thank you.

I had the same problem!
I closed outlook, right-clicked on it, and clicked "New Email Message" then that opened up the email message box, i then right clicked on outlook again and clicked "outlook 2016" and it opened fine.
Was able to close and reopen with no hassle.

Hope this helps.