Unable to login after upgrade

[Paul Smith]

On Sat, 2020-10-31 at 14:20 +0000, Gregory Gamble wrote:
> I'll do a 'shutdown -r now' in a minute, but for now, I recall the
> diagnostic this morning from the X crash suggested the log file
> .local/share/xorg/Xorg.0.log which has the following (again I
> 'sanitised' a few lines):

The problem with this output is, as Liam suggested, you can't just run
"X" by itself.  For many reasons but one of them is that the X server needs special privileges to take over your display, and just running "X" from the command line doesn't bestow those privileges.

It's likely that the error messages in your output were related to
this incorrect attempt, as opposed to the normal, correct way to log
in.  It's always something to look out for when debugging, that you do
something different than what you want to do then debug why THAT
doesn't work, instead of debugging the actual thing you want to do.

I recommend you (a) restart from scratch, then (b) try to log in via
the GUI as you normally would, THEN (c) look at the X log file and find
the lines that look like errors; for example they will be prefixed with
(EE) (for error) and say things like "fatal server error" or "failed
..." or "terminated ..." etc.

Then, post that info.