E: Package 'libavcodec-extra-53' has no installation candidate
94942
How to update libavcodec on ubuntu 14.04?
44991
A lot of missing dependencies when I try to install all software
5942
Where is the alternate installation ISO for Ubuntu Saucy?
10193
Failed to download repository information due to missing CDROM
129939
Unable to install .deb applications with ubuntu software
44846
Package 'upstart' has no installation candidate
133
How can I fix a 404 Error when using a PPA or updating my package lists?
12773
The requested package is unknown
13054
Failing package manager?
117302
"Package 'docker-ce' has no installation candidate" in 18.04
15183
Elementary OS PPA gives “The repository does not have a Release file.” error
31793
The following packages have unmet dependencies!
86963
Why do I get an "unmet dependencies" error when trying to install WINE?
32220
How to resolve Unmet dependencies error?
34069
Why am I getting authentication errors for packages from an Ubuntu repository?
85315
trying to install libgraph
2280
Package system is broken. How to fix it?