I just delete the OEMDefaultAssociations file 🙂

The last time I ran into this, I had to create half a dozen entries in HKCU\Software\Microsoft\Windows\CurrentVersion\ApplicationAssociationToasts in the registry, mostly for IE, but also for .pdf files. Do I still need to worry about the Shell\Associations and FileExts keys in the registry? At this point, I'm just trying to figure out my next angle of attack. I reset the XML to the default 1909 file, but it still threw the same exact reset errors at logon.

Found a few threads of people who are running into the same exact issue as me, right down to the same exact app reset messages: https://www.reddit.com/r/SCCM/comments/eopjw0/avalanche_of_default_app_resets_upon_login/ Doesn't exactly bode well for me for this in-place 1909 upgrade.

Looks like it's a confirmed bug by MS, with no fix yet: https://social.technet.microsoft.com/Forums/en-US/ad37cd15-315e-4f9b-ba34-bcbd987981fc/quotan-app-default-was-resetquot-error-newly-sysprep-windows-10-ltsc-2019-enterprise-image?forum=win10itprosetup My 2 vCPU target devices don't see the errors, but my 4 vCPU target devices do. JFC, Microsoft.