0x800106ba Defender Vista FIX!

I was getting a the error above when Windows Defender would try to start with a clean install of Windows Vista Ultimate. For people with XP or a non-clean install of Vista, this error meant that the Defender Beta was out of date and they needed to uninstall/reinstall. Of course, with a clean install of Vista, you can’t uninstall (or install) Defender. After hours of tryng some solutions for other error codes, the real solution turned out to be pretty simple. You need access to a computer with a working Windows Defender preferably of the same Windows version.

I made my User account the owner of the broken C:\Program Files\Windows Defender folder. Deleted the files inside it. I was able to delete all but one file. I copied the files and folders inside the working Windows Defender folder in Program Files from my Vista Ultimate laptop. I pasted into the broken folder (all files pasted except for the one that didn’t delete.) I noticed the Laptop’s folder had one extra file and two extra folders that were not in the Desktop’s folder. I restarted the computer and now Defender starts and operates normally.

 As a side note, I also did the following before I restarted :

  • Made my User account the owner and deleted the contents of C:\Windows\SoftwareDistribution\
  • Installed Etrust Pest Patrol Demo (If Defender didn’t work I needed Anti-spy software.)