NO_PUBKEY error while upgrading from 12.04
6809
How do I fix the GPG error "NO_PUBKEY"?
28383
Failed to search for file: Failed to download gpg key for repo 'mariadb-main': Curl error (37)
30747
Encountered "/usr/sbin/grub-mkconfig: 8: /etc/default/grub: 4: not found" error while updating
93942
How to fix "Failed to download repository information" error while updating?
51093
MikTeX update error
80899
"no public key available" on apt-get update
145400
Error when trying sudo apt-get update - Python related?
1833
14.04 Cleanly upgrade to ppa:ondrej/php from ppa:ondrej/php5-5.6
4853
Trouble downloading packages list due to a "Hash sum mismatch" error
109064
How to solve the error "Failed to launch Terminal" after upgrading python?
249
How do I fix this "E: Type '*' is not known on line * in source list ..." update error?
48418
W: GPG error: http://ppa.launchpad.net precise Release: The following signatures couldn't be verified because the public key is not available:
4305
How do I fix a "Problem with MergeList" or "status file could not be parsed" error when trying to do an update?
98844
upgrade 14.04 with errors and shows red sign on top
116445
"Can't check signature: public key not found" while upgrading, why?
119943
Where can I find a repository for older unsupported releases?
4248
How to fix apt: Signature by key uses weak digest algorithm (SHA1)?