Windows Defender error code: 0x8050800c

Question

Windows Defender is showing error while attempting to scan (error code:    0x8050800c.)

The error as it displayed was:

"Windows Defender encountered an error:0x8050800c. An unexpected problem occurred. Install any available updates, and then try to start the program again. For information on installing updates, see Help and Support."

As per my observation, this error occured first at 2010/01/28 08:00 am IST (+5:30 GMT) after updating the definition version to 1.75.4.0. Today night, though I have updated to latest version 1.75.94.0 the problem was not solved. Moreover, the software explorer module showing "not available" against the startup items whereas it used to show "permitted" earlier when the Defender was healthy. It is also clear that reinstalling is also not solving the problem as inferfed by seeing the other relevant threads

OS: Windows Vista Home Basic

AV: avast 5.0.377

Please help as my pc is now unprotected.

Moved from Windows Vista

Answer 1

Found this thread and so far it's procedure works

http://social.answers.microsoft.com/Forums/en-US/msescan/thread/a5810b32-5470-46aa-8be4-634f06064131

Answer 2

All links go to invalid URL.

Answer 3

This appears to be an issue with the newest Definition Files as best the rest of us can tell... here is a link to another thread following the problem

http://www.microsoft.com/communities/newsgroups/en-us/default.aspx?dg=microsoft.private.security.spyware.general&tid=a14f19c9-bd65-4bd5-aad1-940700ea1404&cat=&lang=&cr=&sloc=&p=6&mid=b6d1cf00-95e8-4a2f-8db2-702a8682935c

Answer 4

I discovered your post when I did a search for that Defender error code. When I checked my registry entries I realized there might be some issues because I have set up my computer with a separate partition for data, and modified my system environmental variables to point to the second partit

The problem is that while I pointed a certain user to the new partition I left the Guest profile, as well as the system profiles to the normal first partition. However, when my computer boots ALL of the ProfileImagePath entries pointed to the second partition. Once I corrected the registry entries for Guest, Network Service and Local Servie to point back to the original partition, and restarted the computer, that resolved the situation.e

If you use custom Environmental Variables you should definately check your registry entries to see if they are correct!

Hope that helps!

Robert

Here's the page that helped me triage this:

http://social.answers.microsoft.com/Forums/en-US/msescan/thread/a5810b32-5470-46aa-8be4-634f06064131

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Answer 5

Yes - Please refer to Steve's post to resolve this issue: http://social.answers.microsoft.com/Forums/en-US/msescan/thread/a5810b32-5470-46aa-8be4-634f06064131

Let us know if this doesn't resolve your issue.

Thank you

Hazel