Want to reinstall 14.04 over 16.04
67481
How to revert a do-release-upgrade?
69200
How do I reinstall Ubuntu Software in Ubuntu 20.04 LTS version?
34659
How to reinstall many removed packages at once?
112955
How can I upgrade Ubuntu from 19.10 to 20.04 without losing packages?
30645
How to install (old) packages for Ubuntu 9.04?
10709
Can i upgrade ubuntu without losing my apps and files?
8912
Can a system restore reinstall uninstalled programs?
43778
Is it possible to "upgrade" from a 32bit to a 64bit installation?
12578
How do I upgrade to a newer version of Ubuntu?
23236
Manually Installed new Python to /usr/bin, how to get Repo version back?
5820
How to fix the “Unable to calculate upgrade” issue from command line when upgrading from 12.04 to 14.04?
157221
Reinstalling Ubuntu 15.10: "Removing conflicting operating system files" has been running for almost 24 hours
102559
How to install package from newer distribution?
102057
How to keep two versions of an app installed?
36848
How do I safely install an older/newer version of Python?
59088
How to upgrade to a newer release of Ubuntu using the Live CD?
65079
How can I backup my programs/applications, so that after I reinstall a new one, I can still use the backup-ed ones?