Some Ubuntu users are reporting LightDM errors when using a SSD: about half the time when starting the computer, LightDM (the default Ubuntu display manager) doesn't load correctly and only a black screen and a blinking command line cursor shows up. The issue isn't limited to those who are using a SSD, but it's a lot more frequent when booting Ubuntu from a solid-state drive.

I too am experiencing this issue with Ubuntu 12.10 (not tested on older Ubuntu versions because I didn't have a SSD when I was using 12.04) and I've found two possible workarounds which have worked for me so I thought I'd share them with you, in case you're experiencing the same issue.

(GDM 3 in Ubuntu 11.10)

Let's say you have both LightDM and GDM display managers installed on your computer (running Ubuntu, Linux Mint or any other Debian-based Linux distribution). LightDM is default but you want to switch to GDM - to do this, run the command below in a terminal:

Last week we've posted about changing the GNOME 3 login screen background / GTK3 theme via command line but if you want to use a GUI for this, you'll be glad to know that one already exists: GDM3Setup.

Unfortunately, some of the applications (like GDM Tweaker) you could use to change the GDM login screen background / GTK theme no longer work with GNOME 3 / GDM 3, so here is how to change the GDM3 theme or background manually, via command line.

GDM Tweaker is a very simple application that allows tweaking the GDM login screen look: change the GDM background image, hide the username list, enable Compiz and change the GDM login screen icon or GTK theme.

GDM2Setup, a GUI configuration tool for the new GDM (2) is now available for Ubuntu Lucid too.

The installation is the same as for Ubuntu Karmic:

XSplash Background Settings provides a background settings dialog for XSplash and the login screen (GDM) so you can use it to change your XSplash or GDM image and optionally (my favourite): change the XSplash and GDM backgrounds to match your current desktop wallpaper.