During boot, my system is stuck for some reason. I can get to the command line by clicking Ctrl+Alt+F3. After login, what can I do to start the official GUI of Ubuntu 20.04? I tried the following:

 systemctl isolate graphical 

but none of these worked.

I also tried:


and I did see a graphical login screen, but not the usual one; and I could not log in from that screen (I got "authentication error").

I am looking for the most standard and officially-supported solution - I don't need any fancy GUI managers - I just want to get back to work...

  • Try startx in the command line Jul 8, 2020 at 7:51
  • @ArchismanPanigrahi I did this, and indeed I saw the graphical desktop, but after several seconds the system hanged and all I could do was power-off and power-on again. Jul 8, 2020 at 7:57

2 Answers 2


lightdm is not the standard Gnome window manager, it is gdm3, so there is some misconfiguration. Easiest way to try to remedy it is to, when logged in, run:

sudo apt-get install --reinstall ubuntu-desktop

and reboot.

  • 1
    My system is back to life. Thank you so much! Jul 8, 2020 at 8:02

On one of my machines (gpu radeon rx560 =)) After the update, the standard shell ubuntu-desktop also did not start. I tried reinstalling the package, reinstalling the drivers. Nothing helped me.

As a result, the problem was solved by installing another package =)

sudo apt-get install xubuntu-desktop

The shell is similar to the standard one. I haven't lost anything. And the main thing is that it worked and did not have to reinstall the system. If your problem is similar to mine. I recommend trying another shell and not bothering.

  • Not really an answer. The accepted answer has the correct approach (reinstall ubuntu-desktop) and has been confirmed as working and accepted by the OP. This is just install something else. And this "something else" being an entire new/additional desktop environment it presents additional problems the OP (and everyone else) might not want to deal with. Nov 18, 2021 at 10:21
  • This answer is for those who did not work with the first option (reinstall ubuntu-desktop). And there were no additional problems. This is an alternative, it should be different. Otherwise what's the point =)
    – F00x
    Nov 18, 2021 at 12:18
  • And you're assuming those exist based on what? Really, you don't have to post your "2 cents" everywhere. This isn't a forum. Nov 18, 2021 at 12:20
  • The given answer is for those people who will look for a solution by searching. The first solution didn't work for me. I think I'm not the only one.
    – F00x
    Nov 18, 2021 at 12:29
  • The votes are in and they disagree. I suggest you don't do what you're doing and I mentioned in the previous comments. You're at that stage where you know a little bit more than a beginner but not nearly enough to properly interpret/assess a question and provide a reasonably good and useful answer and you're in that confusing mindset that says this can be handled as you would do in a forum when it definitely isn't. That's the problem I see here and other answers that keep popping in the review queue. Just sayin'. Nov 18, 2021 at 12:33

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