After upgrading from Focal to 22.04 cannot install any updates. See: "Package failed to install: Error while installing package: installed neon-keyring package post-installation script subprocess returned error exit status 1." "/dpkg-reconfigure: neon-keyring is broken or not fully installed."
Neon-keyring problem occured after upgading to LTS 22.04 ‘Jammy Jellyfish’.
That doesn't give us too much to go on. Is there anything relevant in /var/log/apt/term.log ?
I had a pop-up message during the upgrade saying: Could not install 'neon-keyring' The upgrade will continue but the 'neon-keyring' package may not be in a working state Please consider submitting a bug report about it Installed neon-keyring package post-installation script subprocess returned exit status 1 The upgrade continued but then said The Upgrade has aborted. Your system could be in an unstable state A recovery will run now (dpkg --configure -a) and The upgrade has completed but there were errors during the upgrade process followed by a fair amount of detail that included the line: gpg: invalid key resource URL: /etc/apt/trusted.gpg.d/home:pzz.gpg I see this info in: /var/log/apt/term.log This was a system where I had previously installed a test version of 'sane airscan'. Subsequently offline updates gave a failure as reported (the post-installation script, exit status 1, failure) I did have a file: /etc/apt/trusted.gpg.d/home:pzz.gpg I think dating from that test version of sane. I rolled back, moved the file out the way, reran the upgrade and all was OK. It may be that just moving the file out the way after the upgrade is sufficient. I think it might be a question of remembering what you might have installed "from elsewhere", whether you still need it and or can remove it.