Fail to sudo apt-get update
5316
Update from 14.04 to 16.04 failed with GPG error
83216
apt get update missing release file
44683
Problem with sudo apt update in Ubuntu 18.04: Post-Invoke-Success if /usr/bin/test -w /var/lib/command-not-found/
108510
apt-get update very slow, stuck at "Waiting for headers"
144036
sudo apt-get curl and sudo apt-get wget gives "Invalid operation"
106931
How to undo sudo add-apt-repository?
2564
apt-get cannot connect to Ubuntu archives
121873
sudo apt-offline install not updating
152823
PPAs will not install "sudo: add-apt-repository: command not found"
116035
Interrupting apt-get dist-upgrade: what could happen?
51598
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
117728
sudo apt update error
59119
apt-get, unmet dependencies, ... "but it is not going to be installed"
151584
Why doesn't the command do-release-upgrade doesn't require sudo?
73973
After typing "apt-get update" terminal says Could not open lock file
127895
403 Forbidden error in sudo apt-get upgrade ubuntu 17.4
65099
Unable to install any updates through update manager/apt-get upgrade