Could not calculate the upgrade, Upgrade 12.04 to 14.04
51768
Could not calculate the upgrade, what happened?
29191
Upgrade to 18.04 from 17.10
154889
Could not calculate build plan: Plugin org.apache.maven.plugins:maven-resources-plugin:2.5 or one of its dependencies could not be resolved
151605
upgrading from 15.10 to 16.04 apt not installed
135383
Unable to update my system Ubuntu13.04: Getting message - requires installation of untrusted packages
2136
How to roll back Ubuntu to a previous version?
67481
How to revert a do-release-upgrade?
61473
Failed to fetch because of size mismatch error while upgrading
43648
Why isn't an upgrade to 20.04 from 18.04 available yet?
67218
update OSX Yosemite & cksum mismatch
110148
Why does `do-release-upgrade` skip a version?
12534
14.04 --> 16.04 failed; apt (>= 1.0.1ubuntu2.13)' is not installed
134530
Can I look at the upgrade log after a distribution upgrade?
125703
Is there a way to run an update and upgrade in one command?
146622
What is a partial upgrade and when is it necessary?
77705
Unable to upgrade in ubuntu
55211
Problem when upgrading to Ubuntu 14.04 from Ubuntu 12.04