I have Outlook 2016 installed on a Windows 10 64-bit system and up till now it’s been working fine. Yesterday, I went to open it and I got the following error message:

"Cannot start Microsoft Outlook. Cannot open the Outlook window."

What’s sad is that I’ve had this EXACT same problem in Outlook 2010 and I even wrote about an article about it over a year ago:


For whatever reason, the solution to the problem in Outlook 2010 is different and none of those methods worked for me when trying to fix it for 2016. So read the previous post and if nothing there works for you, then try the methods listed below.

Method 1 – Delete Registry Key

Click on Start and type in regedit to open the registry editor in Windows.

registry editor

Navigate to the following key in the registry:

HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem

outlook error

Now delete the Profiles key that is under Windows Messaging Subsystem. Restart your computer and try to open Outlook 2010. Hopefully that fixes your problem!

Method 2 – Install Latest Service Pack and Microsoft Upates

The next thing you can try if that didn’t work for you is to install the latest Office updates. You can do this by opening any Office program, then clicking on FileAccount. On the right-hand side, you’ll see production information. Under that, there is a section called Office Updates. Click on the Update Options button and choose Update Now.

This has fixed the problem for quite a few people, so if nothing else is working for you, then definitely install latest Office updates and Windows updates.

Method 3 – Open Task Manger/Kill Process

This problem of Outlook not starting can also be caused by multiple instances of Outlook running without being properly killed. If you go into Task Manger (Ctrl + Shift + Esc), you should only see one Outlook process running.

outlook process

If you see more than one outlook.exe in the process list, go ahead and select each one and choose End Process. Once you have killed off all of the Outlook processes, then try to restart Outlook and see if it loads properly.

So there you have a couple of more possible solutions to this very annoying problem! If you have found a different solution, post a comment here and let us know! Enjoy!

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