Outlook 2016 on my Surface 3 laptop has been working fine until some days ago when I turned it back on and attempted to re-open the programme: since then, everytime I tried to start that desktop application, it remains stuck with the blue rectangle in the middle of my screen, ‘starting’ bottom and the dots moving. I struggle to understand what caused the problem  … may be an update of the Opating System (I am Windows 10 Insider so this could be the case_). Anyway, even disinstalling the whole Office package and reistalling it the probelm remained!

Outlook remains stuck with the starting blu rectangle

As quite always, I found out how to solve the issue looking into the Microsoft Community forum!

I started Outlook in safe mode:  Click Start > All Programs > Accessories > Run > type Outlook /safe and click OK. This time, together with the Starting blu box, also a another windows appeared, asking to choose the profile: I agreed to the proposed one and I had suddenly my email again working, without having to configurate nothing else (even though I previously had uninstalled/installed Office! Evidently the email settings remained somewhere in the PC.
If neither this way solve your issue, you can try to start Windows itself in a safe mode, as ehttp://windows.microsoft.com/en-us/windows-10/start-your-pc-in-safe-mode.