Windows 10: Microsoft Defender Error 0x80070643, how do I fix it?

On Server 2016 and after an in-place upgrade Defender will not start, I cannot reinstall it nor take ownership of the Dir. I have tried all of the usual fixes, repair to Windows update, nope, sfc /scannow, all good, DISM /Online /Cleanup-Image /RestoreHealth, all good, and due to security it seems that I cannot take ownership of the "Defender" directory. The server is fully updated with all patches and I would like to fix Defender so it is operational.What is the problem, and what do I need to do to get it working?Thanks

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Windows Defender Antivirus - KB4052623 4.18.1910.4 - Error 0x80070643

Hi everyone, I have again the same error 0x80070643 updating windows defender antivirus platform. Now with sfc /scannow and dism i don't found errors. Any suggestions? Thanks

 

Windows Update Error 0x80070643 for Windows Defender

Still having issues updating Windows Defender as of 4/3/17, 12:30pm CDT on 10 Pro winver 14393.969 . Windows Update shows Error 0x80070643 but manual update via Defender GUI installed latest virus/spyware definition 1.239.713.0. Re-running Window Update shows everything is up to date.

It's been at least 4 days since this glitch first appeared on my machines. Any thoughts on why Microsoft is delaying a fix? Perhaps to include in next Patch Tuesday 4/11?

 

Error 0x80070643 during Windows Defender update

The official fix to error 0x80070643 problem is found at the Microsoft website listed below. Follow instructions to the letter! It is a silent one time manual fix.....and it works when followed to the letter! No more Windows Defender update problems after
performing it.

https://www.microsoft.com/security/portal/definitions/adl.aspx

Also, follow the thread listed above and here:

https://answers.microsoft.com/en-us...te-error/26689087-6b72-4d25-b31a-bc85a8f13d3e