My computer is a bit old and has 4GB of RAM. I wanted to switch to lubuntu because I've heard it's better with memory. During the installation I had doubts and closed the terminal and finished the installation of lubuntu. But it was loading for a couple of minutes in between. I went to turn on my computer the next day and the lubuntu home screen appeared, but then I switched to 18.04 after logging on.
I ran the command listed here under lubuntu:
and then he did
sudo apt-get update sudo apt-get upgrade
to make sure that all 18.04 files were still intact. One of the files I noticed that was deleted by the psychocat command was ubuntu-desktop. After seeing that ubuntu did not pass the loading page, I ran the ubuntu-desktop installation from the command line and ran the update and update one more time, but the upload page of ubunutu is not yet passed. I should also add that the load page is loading page 18.04 and when you log in to the terminal, it also indicates that Ubuntu 18.04.2 LTS is in the upper left.
Of course, there are many messages like mine about this problem. All the solutions I've tried and all the answers to the problem have to deal with lightdm or an nvidia unit. As ubuntu before lubuntu worked well, there is nothing wrong with my video card and besides that I already tried all the commands with lightdm.
Any help is appreciated.