A few days ago I had a strange issue in Microsoft Windows 7 x64. Every now and then the window/application that I was currently working in lost focus for about a second. And then got its focus back. This was very annoying, i.e. while coding in Visual Studio.

I then tried to track down the problem by killing running applications in the task manager (one by one), but even then the problem persisted.

So I searched for a tool, that would let me identify the application stealing the focus. The tool I found was Windows Focus Logger and it works quite well. All you have to do is click on Start once it is loaded. And it will log all windows focuses with their process name.

With the help of this program I was able to identify the assailant as wermgr.exe – which is the Windows Error Reporting Manager. That’s the program that shows you details, when a program crashes (Send to Microsoft…) But in my case it didn’t show any errors. It just stole the focus every now and then….

If you search for windows focus loss wermgr you will find lots of issues caused by various hardware drivers (i.e. Dell Keyboard, etc.) – but finding a driver causing this would have been a search for a needle in a haystack…

Therefore I tried to deactivate Windows Problem/Error Reporting in the Control panel all together; however a domain group policy did not allow me to completely deactivate it. Therefore I had to use the trick of disabling the Windows Error Reporting Service (by setting it to disabled). Then the focus problem went away as expected…

But of course I was not satisfied with this solution (as it was to drastic in my view). Therefore I took a look at the event log and there was a Windows Service that continually started and crashed in background. But for some unknown reason it never got to the GUI with a crash report…

So I went back to the Windows Error Reporting settings, reactivated all settings that I could find and this time it actually showed an error report for the windows service that was continually crashing in background.

I then repaired the windows service so that it would no longer crash and then my troubles went away…

So the actual problem source was a defective windows service, but wermgr.exe tried to handle that improperly…