Can't convert Ubuntu to WSL 2

[x-cubed]

• Your Windows build number:
  Microsoft Windows [Version 10.0.18917.1000]

• What you're doing and what's happening:
  Trying to convert an existing Ubuntu installation to the new WSL 2 format with

C:\>wsl --set-version Ubuntu 2
Conversion in progress, this may take a few minutes...
For information on key differences with WSL 2 please visit https://aka.ms/wsl2`
Unspecified error

• What's wrong / what should be happening instead:
  Conversion should succeed.

• Detailed logs: lxcore_etl.zip

[x-cubed]

Logs above are from my second attempt, it actually succeeded when I tried a third time.
The only thing different between my second and third attempts was that I had launched bash in between and ran apt-get update && apt-get upgrade.

[dontmint]

It happened the same for me, failed twice and succeed at the third time.

[Biswa96]

Duplicate #4102.

[mkezfarias]

Same thing happened to me, opened ubuntu, closed, restarted windows 3 times, and it finally worked.