You really got to have constant backups so you can recover from situations like this. As it is you'll likely have no choice but to repeat that work
#Recover .vhdx wsl data
outer stag
prisma basin
Just copy the entire vhdx to a backup location for now. It's located in the distro subfolder within %localappdata%\Packages
Your install is fucked and it'll likely take more time to fix it than just reinstalling. You can just create a hyper-v debian VM on a fresh install and attach the vhdx to that.
prisma basin
Yes. The only reason you might want to disconnect the non-primary drive(s) is that windows will use the first EFI System Partition it finds. If you've never used your other drives for (EFI) os installations, then that's not a concern. It's just a minor annoyance to have the ESP on a separate drive from the c drive
Afaik, the error you're receiving is something that happens after a Windows insider build is very expired. So much is gonna be broken. If you switch virtualbox to virtualbox mode instead of hyper-v mode you may be able to launch the VM.
It looks like you'll need to disable hyper-v in windows to get virtualbox to use its own virtualization
prisma basin
I suspect you never actually enrolled your install into insider, and so you've been on the same build since you installed. Insider builds won't update until you've registered them in settings.
The vhdx is a container for a virtual disk, containing the several partitions created by debian. While you can mount the disk in windows, it will not be able to read the partitions within since windows doesn't support ext4/btrfx/xfs or w/e fs debian uses. You just need a functioning virtual machine that supports ext4/btrfs/xfs/etc to attach the vhdx to
There's absolutely no reason to think the vhdx is corrupted, so just back it up and open it later when you have a working install of windows with hyper-v. I have no idea why cmdrkeene thinks you've permanently lost access to a vhdx you have access to.
The vhdx is a file, just copy it somewhere safe. Unplug the drive that contains the file during reinstall if you're really worried that you'll accidentally delete the partition during the Windows install.