# Ubuntu 18.04 login loop **URL:** \ **Category:** Linux\ **Created:** [December 10, 2020, 5:42pm UTC](https://forums.developer.nvidia.com/t/ubuntu-18-04-login-loop/161606 "2020-12-10T17:42:59Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![rok](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@rok](https://forums.developer.nvidia.com/u/rok)\ **Post date:** [December 10, 2020, 5:42pm UTC](https://forums.developer.nvidia.com/t/ubuntu-18-04-login-loop/161606/1 "2020-12-10T17:42:59Z")
Hello, We are experiencing the login loop problem, presumably after the last system update. Everything was working fine (driver, CUDA and CuDNN is installed) until last system upgrade, but now something broke. I already tried common solution found googling like permission on /tmp folder and .XAuthority (which is not existing), then when I tried nvidia-smi I got error: _NVIDIA_ - _SMI has failed because it couldn’t communicate with the NVIDIA driver_ . Make sure that the latest NVIDIA driver is installed…" so now I think that some part of the upgrade broke nvidia driver… Attached the nvidia-bug-report. Any help? [nvidia-bug-report.log.gz](https://forums.developer.nvidia.com/uploads/short-url/hdSXG0vNhV1iyBUYGHeFplEo4BG.gz) (62.4 KB) ---
**Author:** ![generix](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/generix/32/16024_2.png) [@generix](https://forums.developer.nvidia.com/u/generix)\ **Post date:** [December 15, 2020, 8:52pm UTC](https://forums.developer.nvidia.com/t/ubuntu-18-04-login-loop/161606/2 "2020-12-15T20:52:55Z")
How did you install the driver? please post the output of dkms status ---
**Author:** ![rok](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@rok](https://forums.developer.nvidia.com/u/rok)\ **Post date:** [December 16, 2020, 9:34am UTC](https://forums.developer.nvidia.com/t/ubuntu-18-04-login-loop/161606/3 "2020-12-16T09:34:12Z")
Hi, at the end I solved my problem. That was not my computer so it was a little bit tricky to undestand what they did… Anyway I realized the driver was installed using the .run installer a couple of years ago, while there was a recent system upgrade. I think since the driver was never updated a 2-year mismatch between driver and xorg packages version was the caused the issue. I first uninstalled the driver using nvidia-uninstall , this gave me warnings about driver installation altered and about it cannot restore the original xorg configuration (backup was not made). Loop persisted. Then I deleted /etc/modprobe.d/blacklist-nvidia-nouveau.conf that was created according to [Installation Guide Linux :: CUDA Toolkit Documentation](https://docs.nvidia.com/cuda/cuda-installation-guide-linux/index.html#runfile-nouveau-ubuntu). Loop persisted. At this point i realized that there was another file blacklisting nouveau and was /etc/modprobe.d/nvidia-installer-disable-nouveau.conf I deleted that file too… reboot and GUI was back with nouveau. I then installed latest driver using sudo ubuntu-drivers autoinstall and now everything is working! ---
**Author:** ![nadeemm](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/nadeemm/32/367020_2.png) [@nadeemm](https://forums.developer.nvidia.com/u/nadeemm)\ **Post date:** [October 12, 2021, 6:32pm UTC](https://forums.developer.nvidia.com/t/ubuntu-18-04-login-loop/161606/4 "2021-10-12T18:32:07Z")
Closed on October 12, 2021, 6:32pm UTC