I am unable update ubuntu 12.04
728
Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?
80899
"no public key available" on apt-get update
123455
Unable to update Node JS - keeps returning to old version [Ubuntu 15.04]
13832
How to update Ubuntu terminal?
64509
Can't update from official repositories [Error 409]
134080
Still can't upgrade? Is there a new delay?
15687
How do I resume a release upgrade?
43648
Why isn't an upgrade to 20.04 from 18.04 available yet?
46720
sudo apt update error: "Release file is not yet valid"
135383
Unable to update my system Ubuntu13.04: Getting message - requires installation of untrusted packages
46424
Cannot update software center repositories
87236
How to upgrade Ubuntu 12.04 to 13.10?
7580
How to safely upgrade from an older Ubuntu version to a newer one?
146675
Error 101: Network is unreachable when trying to update
10023
'Some index files failed to download' while updating
50810
No upgrade available for 19.04 from 18.10
154622
How do I resolve this installation error?