Definition Update for Windows Defender - KB2267602 (Definition 1.213.5087.0) - Error 0x80070643

The fix that worked for me was to install Avast (free version) and then uninstall Avast. Windows Defender update errors stopped. Why?

Thanks for the feedback, André Kennedy. This really isn’t a Windows Update issue, as the OP quickly discovered. It’s just a case where Windows Defender doesn't get switched off in the registry when the third-party AV app is installed. So you have to either reinstall the third-party app; use the shortcut method that I’ve described above; or turn Defender off in Group Policy. People with the Home edition of Windows 10 can just download and run the Turn_Off_Windows_Defender.reg  file to disable Windows Defender in the Group Policy registry key:

http://www.tenforums.com/tutorials/5918-windows-defender-turn-off-windows-10-a.html

GreginMich

I’m not really sure why this discussion is being up-voted like it is, but judging from the vote count, it must be mtcdnp’s report that the troubleshooter doesn’t work that’s responsible for generating all the enthusiasm. Of course I didn’t really want to spoil the party by finding something that actually does work, but I did just happen to stumble upon a method that appears to fix this problem completely, and in a heck of a hurry – without ever having to touch the registry or use some external download to do the dirty work for you.

I had just reproduced this issue for a third time in order to confirm that Windows Defender would actually start up if Avast was disabled, since this would allow Windows 8.1 users to turn off Windows Defender in the Settings tab and thus resolve the issue.

After reproducing the issue, I disabled the Avast shields “permanently” with the Avast shields control (right-click on the Avast icon, and select Avast shields control > Disable permanently), and I found that this did in fact allow me to turn on Defender.

Then I just left Windows Defender turned on and went back and enabled all of the Avast shields with the shields control – and this turned off Windows Defender as expected. But when I closed the Windows Defender UI and then tried to reopen it, I got the familiar “This app has been turned off and isn’t monitoring your computer” message. That message normally means that Windows Defender has been properly disabled. So I checked the registry, and sure enough, the DisableAntiSpyware and DisableAntiVirusDWORDs actually had been updated to the proper value of 1.

Then it suddenly dawned on me that I had just inadvertently replicated the fix proposed by hughie55 in the following windows discussion thread – but in a highly condensed form that didn’t even require rebooting between steps:

http://answers.microsoft.com/en-us/windows/forum/windows\_10-update/definition-update-for-windows-defender-kb2267602/d4edd314-a438-4ac2-b7a9-dc1c45a1ef62

So now I’m fairly confident that we might be able to generalize this uber-simple fix to some other AV products as well. In my case, I was able to just turn off the third-party AV app (Avast Free); start Windows Defender; and then turn the third-party app back on while Windows Defender was still turned on. But in other cases, you might need to repeat this procedure a couple of times, or maybe reboot between steps. Anyhow, people who aren't really dead set on waiting for Microsoft to fix this issue might want to just go ahead and give this fix a try.

GreginMich

For weeks now keep getting the message:

"Definition Update for Windows Defender - KB2267602 (Definition 1.213.5087.0) - Error 0x80070643"

While the computer seems to run ok, in the mean time I cannot update windows 10...

Yes, ME TOO!!!  I have NIS and it takes over the role of win def.  Like everything else with windows and ms in general:  THIS IS OUR OS AND IF YOU HAVE ANY TROUBLE WITH OUR DS TECHS---T. S.!!  It would be easy for them to allow US, THE DUMB F!!!!!!'S THAT KEEP MS "ALIVE" AND "EMPLOYED" AND MILLIONAIRES, TO SIMPLY "HIDE THE G D UPDATE----BUTT---NO......let's act like "idiots" and "ignore " the SIMPLE WAY TO CORRECT THIS DUMB **** PROBLEM!!! 

So now we will ALL HOLD OUR BREATH(NOT) FOR A "SOLUTION" RATHER THAN A BS, NON-PROBLEM-SOLVING REPLY!!!

I am having very similar problem - have 3 PC's with W10 - all using Windows Defender.

2 desktops OK but Laptop (which is an upgrade from W7 via MS rather than a new installation.

Was OK but twice a day now automatic update always fails as above.

Ordinary W10 updates, including reboot, always seem fine,

Updating Windows Defender directly occasionally works BUT most times fails with a window saying it did not update due to a network or internet connectivity problem.

Updating WD by downloading the latest signature update and then running that always seems to work and when updated the Windows Update does not fail - as now 'up to date'

So far cannot find anyway of curing this!

@mtcdnp -

To manually download latest signatures try executing the following command : "%programfiles%\windows defender\mpcmdrun.exe" -signatureupdate -http

The error you are seeing is a generic Error_Install_failed code.  Can you access the following file (\windows\temp\mpsigstub.log) and post the entry with the error code.  I'd like to see were the error occurs.

Thx,

CJ.Eichholz (MSFT) - Microsoft Antimalware

CyberDust: +msft_cjeichholz

Twitter : @msft_cjeichholz

This post is provided as-is with no warranty or support.