I have Outlook 2010 installed on a Windows 7 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.”

Method 1 – Delete Registry Key

Click on Start and type in regedit to open the registry editor in Windows 7.

registry editor

Navigate to the following key in the registry:

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

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 2010 service pack, which is SP 1 right now.


office 2010 sp 1

This has fixed the problem for quite a few people, so if nothing else is working for you, then definitely install SP 1 and also download all the latest security updates from Microsoft using Windows Update.

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.