I have a 2011 Thinkpad T420 with Lubuntu 18.04 and Windows 8.1
When I was helping my friend install Lubuntu on his Core 2 Duo Macbook, I noticed that lxQt actually works now. In fact, it's what Lubuntu boots into by default now. I figured that it must work on my version of Lubuntu, even though I remember lxQt never working for me before because it wasn't done/supported yet (I guess I assumed that I had the latest version). I have been switching between LXDE/i3wm for a couple months.
However, upon booting into lxQt, I received the error message
unable to launch "/usr/bin/startlxqt" X session --- "/usr/bin/startlxqt" not found; falling back to default session.
After closing this error message I can't do anything. It's just a black screen with an "x" for a cursor.
What I'm guessing is happening is that I don't actually have lxQt, so the system doesn't know what to do. I'm not sure why there is even an option to use lxQt if it is not supported in 18.04. I should probably mention that I have it where I login automatically, so I can't just change the DE from the login screen. I was hoping there was a way to change what DE it boots into from the GRUB command line or maybe by changing a file from a live installation. Or maybe I could actually install lxQt to that path so that I can actually boot into a DE. Worst case scenario I do a fresh install after getting all my data off the drive. Also, I will make it to where I can sign in so that this doesn't happen again. Thanks in advance guys.