before you ask, I have searched and have not found a solution, despite reading the answers to several similar questions (question 1517643 is spot on, but doesn't appear to have any answers; other questions were asked before the stable 24.04 release). Plenty of suggestions, but no certainty.
So, I was on 22.04 (Jammy), and I wanted to update to 24.04 (Noble). I successfully ran apt-get update, rebooted, and ran a do-release-upgrade.
Everything looked good, but after a while it popped a screen saying that it couldn't reach the snap for Thunderbird. The options included continuing or aborting. I carefully chose Abort, but it appeared to continue the upgrade (!!). 2 minutes later it said the upgrade had been completed with errors.
After checking AskUbuntu re. the Thunderbird/Snap issue, I figured I could fix that, so I rebooted. Bad move. Now I have the grey screen with "Oh no! Something has gone wrong.".
Should I reboot to recovery mode, and if so, what can I do to fix the problem?
Thanks in advance for all helpful suggestions.
John