Can't update because of "untrusted" packages?
11166
"Require Installation Of Untrusted Packages" while upgrading with the update manager
117852
"Package dependencies cannot be resolved" error when installing software
133
How can I fix a 404 Error when using a PPA or updating my package lists?
145917
Removing broken packages on distro update (13.04 to 13.10)
91611
Unable to use package manager due to "exclusive lock" error
105451
apt update: Could not handshake: An unexpected TLS packet was received
135575
How to fix a "Failed to fetch binary-armhf/Packages" error during apt-get update?
154622
How do I resolve this installation error?
151656
Installing from source. How to resolve dependencies without destroying the package manager
135985
Apt-get saying "Unable to correct problems, you have held broken packages."
135383
Unable to update my system Ubuntu13.04: Getting message - requires installation of untrusted packages
91491
How can I get "delta" packages to optimize apt-get upgrade downloads?
43579
I cannot install new packages: "Could not get lock /var/lib/dpkg/lock"
85724
Cannot update/get any packages. gedit not installed
5162
How to fake a package version installed?
1632
How do I fix a "Failed to download package files" error?
4853
Trouble downloading packages list due to a "Hash sum mismatch" error