It may appear to be an Xorg or lightdm/gdm/mdm error but in reality for many users with this issue, it's a driver conflict and issue. I had a system that had two GPUs, an Intel and Nvidia GPU. The only thing that got it working was to remove the nouveau driver and blacklist it so it never came back, then the Intel GPU works fine without these issues. Solution sudo rmmod nouveau add nouveau/other driver to blacklist edit th........

This happens on some systems due to a video issue with Intel Videocards, after you see the kernel load you may see almost immediately that you get a black screen. The following kernel parameters usually solve it: nomodeset i915.modeset=0 xforcevesa some people just use "nomodeset" and others use "i915.modeset=0". I think nomodeset may also do the same for each video driver so it may imply i915.modeset=0 anyway but I am not sure.........

You'll see the following and the boot process will freeze: io scheduler noop registered io scheduler anticipatory registered io scheduler deadline registered io scheduler cfq registered (default) I have struggled with this issue on vari........