Somewhere in your past, a tutorial told you to add a PPA. Now it is dead, renamed or missing your release - and it takes the whole update command down with it. This page shows how to find that one file, switch it off without deleting anything, and prove it was the culprit.
Here is the pattern to recognise: Ubuntu's own lines say Hit, one line says Err with ppa.launchpadcontent.net in the address, and the summary blames a repository with no Release file. That is not Ubuntu failing - that is one third-party source you added earlier. The fix is small, reversible, and lives in a single file. This page walks it, and then deals honestly with the software that PPA was feeding you.
A PPA (Personal Package Archive) is a third-party source you or a tutorial added at some point - for a newer app version, a driver, a theme. Ubuntu's own repositories and every PPA are checked together in one apt update run, and apt reports the run as failed if any source errors. So one abandoned PPA - its owner stopped publishing, renamed it, or never built packages for your Ubuntu release - produces the full red-text failure while everything else quietly succeeded. The Err line's address gives it away: if it contains ppa.launchpadcontent.net, a PPA is your culprit.
Every added source lives in its own small file, which makes this fix clean and reversible.
ls /etc/apt/sources.list.d/someteam-ubuntu-ppa-jammy.list..sources file in the same folder instead of a .list file - the same steps apply to whichever file names the failing PPA.Be clear about what disabling does and does not do. Programs already installed from that PPA stay installed and keep working - they simply stop receiving updates from it. If the PPA was your only source for an important app, look for its current home: PPAs get renamed, move to official repositories, or are replaced by a Snap or Flatpak from the same developer. What you should not do is hunt for a random replacement PPA from an unknown owner to silence the gap. A PPA's packages install with full system privileges, so a PPA is a trust decision, not just a download link - keep the list short and known.
The video finds the failing PPA in the output, disables its file, and reruns the update clean.
▶️ Watch Full VideoNo. Disabling a source only stops apt from checking it for updates. Programs already installed from the PPA remain installed and keep running normally. They will simply not receive newer versions from that PPA anymore - which is exactly what you want when the PPA is broken or abandoned, since it was not delivering trustworthy updates anyway.
Ubuntu's repositories are maintained and signed by the Ubuntu project itself. A PPA is published by an individual or a team on Launchpad, under their own control - anyone can create one. That freedom is useful for newer software, but it means a PPA can be abandoned, renamed or emptied at any time, and its packages install with the same full privileges as official ones. Trust matters more, not less, than with official sources.
The commonest reason is a release mismatch after an Ubuntu upgrade: the PPA publishes folders per Ubuntu codename, and if it has no folder for your new release, the address apt asks for does not exist and the server answers 404. Owners also retire or rename PPAs, and some remove old release folders to save space. In every case the fix is the same - disable it, and if you still need the software, find where its publisher officially offers it now.