Update: This is a bit of an outdated answer at this point. If you are running an older version of WSL that was installed prior to Windows 10 or 11 22H2, then this may be the correct answer on how to uninstall. However, if are running the Store-version (or UWP version) of WSL, then please see my newer answer (and/or other users' answers, if present).
Can WSL 2 be installed from scratch without installing WSL 1 before?
No. The base WSL support is required for WSL2.
What is the most secure and advisable process to remove WSL completely?
Here's the best info I have on removing everything related to WSL.
It sounds like you consider the existing instance a lost cause, but if you'd like to back it up for posterity, you can start with:
wsl --export <distroname> archivename.tar
Then remove the existing distro installation(s):
- Any distro you installed from the Store, you should first remove through "Apps & Features" (a.k.a. "Add or remove programs") in Windows. This also goes for distributions installed manually via downloaded Appx package.
Then check to make sure nothing is left. From PowerShell or CMD:
wsl -l
wsl --unregister <distroname>
You may want to just install a new distro at that point from the Store. It's unlikely that any additional reinstallation of the other components is going to make a difference. But if you do want to remove them:
From "Apps & Features" (a.k.a. "Add or remove programs") in Windows, remove the "Windows Subsystem for Linux Update". I'm fairly certain this is the Linux kernel update. Probably reboot if you want to be sure it's fully gone before the next step.
From "Turn Windows Features on or off", disable "Windows Subsystem for Linux. According to the comments, a reboot may be required before the next step.
From "Turn Windows Features on or off" in Windows, disable the "Virtual Machine Platform". This is the WSL2 Hyper-V support.
Reboot.
When you are reinstalling from there, I'd appreciate it if you could confirm that "Windows Subsystem for Linux Update" returns to Apps & Features after installing the kernel update package (Step 4 in the Install doc). I will update this answer based on that info.