Fix ubuntu apt-get and release upgrade errors

Fix fetching updates:

When you get “Unable to fetch some archives, maybe run apt-get update or try with –fix-missing?” error do this:

cd /etc/apt
mv sources.list sources.list.old
lsb_release -a
sudo cat sources.list.old |grep RELEASECODENAME |grep -v "#" |sed 's|us.archive.|old-releases.|g' >> sources.list

(del and retype >> in console if error occures)

 

https://www.tech-notes.net/issues-wit-apt-ubuntu-12-04/

https://stackoverflow.com/questions/38743951/unable-to-fetch-some-archives-maybe-run-apt-get-update-or-try-with-fix-missin

https://askubuntu.com/questions/91815/how-to-install-software-or-upgrade-from-an-old-unsupported-release/91821#91821

 

Resume a release upgrade:
https://askubuntu.com/questions/346678/how-do-i-resume-a-release-upgrade