Windows Defender Error Code: 0x80073afc

I had this error message. I tried to fix it by restoring windows to where it was two month ago. There was some errors and restore didn't work. Finally I installed whole windows from beginning, it helped. Because laptop is more than two years old there was 160 windows updates to do. I installed first 80 windows updates without problems. Then I tried to install the rest 80 windows updates and same problem occured!! There was an option to undo those update installations, which I did and and no problem anymore. Now my computer have no automatic or manual windows updates and everything have worked for last 3 weeks without problems (and there is more than 80 windows updates available). So this problem have something to do with the latest windows updates.

I thought the problem was resolved with the systems restore but now I'm getting the same error message again.

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I'm sorry to hear that, Robynn.

• When did it start again? Was it with the new and current antimalware client version or engine recently installed?
• Is it the same error code 0x80073afc alone, or...?
• Any recent Windows update (included with past May Tuesday Patch or otherwise) you might identify as suspicious to be related to the issue?

Would ask you to please do not do a system restore this time (just yet) but run a SFC instead. Then, upload your logs to your OneDrive public folder and post here a link to it so we can take a look at it.

Please note that this issue has been escalated to MS Antimalware Team, so please provide as much details as you can about it and keep us posted/stay tuned to this thread.

Thanks in advance. Your feedback is very important to our Community.

Per your reply on June 2, 2015...

I believe is started again sometime mid April and I get the same error code.

I don't think there are any updates that I would identify has suspicious.

I ran a SFC (I'm not sure how to upload the logs to my OneDrive) but it says that: 

Windows Resource Protection found corrupt files but was unable to fix some of them. Details are included in the CBS.Log %WinDir% \Logs\CBS\CBS.log.

See: How to view details of the SFC process to produce your Sfcdetails.txt file. Just follow the instructions provided in KB929833 to copy the information from your CBS.log to the Sfcdetails.txt file, so you can read it. Then, you may copy/paste here only relevant details from it (about corrupted files that WRP is unable to fix), or you may choose to upload the whole file to your OneDrive's public folder, and post here a link to its location so we can take a look at it.

Please do this with your 'first' scan log file that indicates the "unable to fix" error message. Then, reboot to safe mode and run the scan again in safe mode. Upload this second scan log as well.

Please also respond to Support Engineer (SE) Uttam Yadav private message (PM) with any additional information/files that is requested there as part of the investigation being handled by the MS Product Group.

You would have already noticed that he also PM'ed other affected members participating in this-your thread (started on March 24 - one of first reports received) since this one (and other threads reporting similar issues)) is being monitored by them as a reference (I think) proven that a system restore is not a final solution but only a workaround. Hence, PA Bear's hint to unmark Babu V's 25 March 2015 reply as ANSWER - action which you already did. Thank you.

Apologize for the inconvenience. Thanks for you collaboration to this matter.

I have also had this exact error, I believe that my error code started on 23/05/15, the cause of the problem for me was an application that chrome had installed that would remove unwanted software that was affecting the way the Chrome works. I believed that this application/program was legitimate because it had actually came onto my screen as an update for Chrome rather than any usual ad or popup, Once this had installed it asked me to restart my computer, when I restarted my computer Windows Defender had been disabled, with the error:

there is no way to launch Windows Defender through any means that I have found.

And yes I have followed all of the steps that were posted on this thread and so far none have worked,

I did not however restore my computer as there are no longer restore dates that go back to the date that the problem occurred.

Shall I run this SFC scan and send you the details?

Robynn, on 30 March 2015 & in reply to a post of mine, you told us...

Q: Are you still getting the 0x80073afc error? Does Action Center still say that Windows Defender is turned off?

A: No I don't get the error message anymore and Windows Defender is turned on.

Has the 0x80073afc error returned and/or is Defender turned off again or...?

Note: If KB3022345 is listed in Installed Updates, you can disregard the "corrupt files" result when running SFC for now. See the Additional Information section on this page: https://support.microsoft.com/en-us/kb/3022345