Ubuntu 14.04 log in fails and returns to log in screen, and runs in a very low resolution

Question

After installing a recent update (Can't tell you any details since I can't access anything), I can no longer log in on Ubuntu 14.04. I just get booted back to the login screen after a second or two whenever I try, and it plays an error sound but displays no other new information. Same thing happens if I try to start a guest session, but if I enter the wrong password it shows a password error as usual. The login screen also runs in a very low resolution (Probably 800x600 or something), but I have no extra screens or anything else to cause problems. On my Windows partition on the same drive, everything functions normally.

EDIT: This thread describes a similar issue, (without the low resolution), but I tried the commands suggested in the top post, and I don't have any of those problems. I've tried reconfiguring lightdm, replacing it with gdm, and tried deleting /Xauthority, but nothing makes any difference.

Some of the answers in the other thread vaguely suggested that it might be a graphics issue, which seems likely given that my resolution is wrong. However, they didn't provide any solution, so I'm still stuck with that.

@Fabby The issue is similar, but without the resolution issues, and the fixes didn't work. Added more info at the bottom of the main post. — Morten Lohne, Jul 11 '15 at 13:15
I've got 760 and had 'constant drop back to login screen' after an update from 14. 04 to 14.10. It worked again after reinstalling the drivers: http://askubuntu.com/questions/643777/ubuntu-15-04-login-fails-and-returns-to-login/644341#644341 — Velkan, Jul 12 '15 at 17:09

score 0 · Accepted Answer · edited Dec 02 '15 at 11:12

For anyone else who has this issue (low resolution and login loop after update on Ubuntu 14.04) I've just encountered it on my machine... It has a nvidia graphics card too (GTX 750ti) which seems to be the source of the problem. I booted in safe graphics mode and selected the option "drop to root shell prompt". From here I logged in and then reinstalled the nvidia driver, which for me was conveniently still in Downloads.

sudo nvidia-xconfig
cd ~/Downloads
sudo sh NVIDIA-Linux-x86_64-352.55.run

I followed the install prompts (saying continue/OK to everything!) and then rebooted. Now everything is back to normal again :)

I've not tested this, but if you don't have the appropriate nvidia driver you could find it on the nvidia website: http://www.nvidia.com/Download/index.aspx?lang=en-us

And then retive it using wget:

wget "http://uk.download.nvidia.com/XFree86/Linux-x86_64/352.55/NVIDIA-Linux-x86_64-352.55.run"

Ubuntu 14.04 log in fails and returns to log in screen, and runs in a very low resolution

1 Answers1