Have you read the Ubuntu Desktop Guide? That must surely be the first place to go next. The Desktop Guide is part of a default install of Ubuntu. It...
On Ubuntu I used update-manager -d -c according suggestion in https://iso.qa.ubuntu.com/qatracker/milestones/464/builds/316648/testcases/1310/results...
Appeared to be completely my own fault. I had "fixed" an ip conflict a few times already not understanding I had a setup which produced new conflict...
I've used it myself too (many many times, I'd not be surprised if it was 50% of the times I'd upgraded, though it may have been few times than that;...