Windows 10 20H2 update crashes... Windows 10 crashes at the end of installing AV

[DavidR]

Hi, the devs would need some logs...

Follow instructions: https://support.avast.com/article/33/ and post the File-ID and/or name of the Support-File here afterwards.

I think the devs could create themselve a VM with Windows 7 and then update to Windows 10 20H2 using the Mediacreation tool ! can't they ?
<snip>

Whilst they probably could do that yes, but what they can't do is exactly replicate your system.

Hopefully your logs will help them with the problem.

[malfretup]

Hi, the devs would need some logs...

Follow instructions: https://support.avast.com/article/33/ and post the File-ID and/or name of the Support-File here afterwards.

I think the devs could create themselve a VM with Windows 7 and then update to Windows 10 20H2 using the Mediacreation tool ! can't they ?
<snip>

Whilst they probably could do that yes, but what they can't do is exactly replicate your system.

Hopefully your logs will help them with the problem.

Because I had the problem on many computers updated from Windows 7 directly to Windows 10 20H2 or from Windows 7 to Windows 8, 8.1 10 and go to the latest and have the same problem, I supposed that the problem was Windows 7

So I made a Windows 7 VirtualBox VM, with Nothing else except Windows, directly make un update with the MediaCreationTool, and so go to Windows 10 20H2 and after, install avast… So with all those explanation, they can, for sure, replicate exactly the system

[Asyn]

So because I am cool and I have some time to waste… here are two reports ID :

VH3NR (after I uninstalled avast using avast clear from safe mode and reboot the computer)
IM58P (the report has been made from safe mode because the computer is rebooting in loop)

I hope it will help

Thanks, the devs are informed.

[Asyn]

Hi, the devs think it might be related to HVCI. Do you have HVCI/Core isolation/Memory integrity enabled..?

[malfretup]

Hi, the devs think it might be related to HVCI. Do you have HVCI/Core isolation/Memory integrity enabled..?

Absolutely not
As I said, this problem appeared only on computers who were first on Windows 7 and upgraded from Windows 7 to Windows 10 20H2 not reguarding if there was other Windows between Windows 7 to Windows 10

[Asyn]

OK, the devs are trying to reproduce it...

[malfretup]

OK, the devs are trying to reproduce it...

They will easyly I think

[Marshal_Kilgore]

I can confirm the problem reported by malfretup:

My laptop was updated from Windows 7 to Windows 10 a year ago. The update from Version 2004 to 20H2 via MediaCreationTool failed when migrating applications. After uninstalling Avast Free (20.8.2432) with avastclear the update of Windows 10 was successful, but reinstalling Avast resulted in the described boot-loop.

Manually installing KB4562830 on the other hand worked fine. So the cause are most probably remnants of Avast in the Registry/WinSxS from its installation under Windows 7.

Albeit only few users would be affected this time, it should be fixed before the next Feature Update requires an inplace update.

[davews]

I had absolutely no issues updating from 2004 (fully updated) to 20H2 using Windows Update, that was very quick and painless. I guess you are using the media creation tool because 20H2 was not yet shown as available for your machine.

[Asyn]

OK, the devs are trying to reproduce it...

They will easyly I think

Dev-Info: I can confirm we've reproduced the issue in VirtualBox and we're trying to figure out, what is the cause (and whether it might be caused by our AV or not). So far the issue only manifests on systems upgraded from Win7, not on clean installations.

[Asyn]

Dev-Info: I can confirm we've probably found the cause - there seems to be an issue in SAM (security account manager) database (corruption), that manifests when lsass.exe (https://en.wikipedia.org/wiki/Local_Security_Authority_Subsystem_Service) tries to access it. The issue can be triggered not only by Avast installation, but also plainly by opening lusrmgr.msc (local users and groups manager), and clicking Groups directory. This tool also accesses the SAM via LRPC call to lsass.exe Warning: If the issue gets triggered, it may not be possible to log into the system again and full recovery/re-installation might be needed.

This issue is therefore not caused by Avast, we just trigger it during installation. We will do our best to contact Microsoft and support them with artifacts from our investigation (we should be able to provide full memory dump) to resolve the issue, but we sadly cannot promise anything going from there.

[malfretup]

Dev-Info: I can confirm we've probably found the cause - there seems to be an issue in SAM (security account manager) database (corruption), that manifests when lsass.exe (https://en.wikipedia.org/wiki/Local_Security_Authority_Subsystem_Service) tries to access it. The issue can be triggered not only by Avast installation, but also plainly by opening lusrmgr.msc (local users and groups manager), and clicking Groups directory. This tool also accesses the SAM via LRPC call to lsass.exe Warning: If the issue gets triggered, it may not be possible to log into the system again and full recovery/re-installation might be needed.

This issue is therefore not caused by Avast, we just trigger it during installation. We will do our best to contact Microsoft and support them with artifacts from our investigation (we should be able to provide full memory dump) to resolve the issue, but we sadly cannot promise anything going from there.

OK, it's great that the Devs found the bug using all the clues I provided and I was quite sure that the problem was one from Microsoft... I hope they will correct it quickly, so I could install back again avast on my upgraded computers

Actually, Avira is installed... and I prefer Avast lol

I keep an eye on this subject

[Asyn]

Info from Microsoft: https://docs.microsoft.com/en-us/windows/release-information/status-windows-10-20h2#1514msgdesc

[malfretup]

Info from Microsoft: https://docs.microsoft.com/en-us/windows/release-information/status-windows-10-20h2#1514msgdesc

Great news... Now we have to wait a little time before having an update

[moeller.rainer]

For me it seems that Windows 2020-11 Cumulative Update has solved the problem.
I was able to update a VM installation that has failed before on both ways:
- Installing the 2020-11 updates on Windows 10 Version 2004 and updating to Windows 20H2 with installed Avast Free Antivirus
- Removing Avast and updating to Windows 20H2, then installing the 2020-11 Cumulative Update and reinistalling Avast afterwards

Though I wouldn't go any risk and  won't make the update without a reliable backup/restore path