I use Ubuntu 16.04. A couple of days ago I found that several programs, particularly R, KRDC, PlayOnLinux, cannot be launched and the OS does not see them at all. I looked at the installed packages with
apt list --installed but also did not find any traces of them.
I repeated the installation of KRDC and it starts to work and founds all previous settings. However I do not think that this is a right way, since for R I'll need to re-install a lot of packages and dependencies.
I suspect that it was happened after one of automatic updates. But I did not launch those programs for a week or two and now I don't know how to detect what was wrong and how to fix this. Could you advice me something?
I found partially broken Software center. Software & updates menu did not work. Re-installation fixed this. Probably there are more damaged software.