I looked down at my Windows 7 taskbar today to find my virus scanner absent. In fact according to the shortcut and Add/Remove Programs Microsoft Security Essentials was gone.
So I poked around in the logs some, hoping against hope I didn’t have some weird backdoor thingy that had uninstalled it for me. According to the logs it was uninstalled as part of some Windows Update hijinks. Ironically I commented just this morning that I always advised people to stay right up to date rather than trying to micromanage that stuff.
Well something went wrong with the update and MSE could not be reinstalled. I got no notice of this from Windows Update scarily enough. Once I knew that it was Microsoft removing my virusscanner I felt much better. So I downloaded a new installer and fired it up. It failed (and failed and failed).
Eventually I did a Google search on the error code, “0x8004ff07”. It looks like this is something of a common problem, and other people have had it. What wasn’t real clear was how to fix it. Somewhere, and I apologize because I’ve lost the link so I can’t credit them, I read something about removing the uninstall registry key, “[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Microsoft Security Essentials]”. Well though it doesn’t appear to work for everyone, that worked for me. After that I was able to reinstall MSE. Phew.
