I got the upgrade notice. Went to the process. No error message.
Re-start gets me past Grub. Then I get this, can't enter user profile
W
I will assume that you tried rebooting more than once?
Looking up on google for MMIO read fault, two top cases offered had to do with an Nvidia graphics driver.
Yes. And same result
If I do an Alt-F2 I get an ask for a login
But password not working
W
Remove xf86-video-intel
???
How can I do that without entering the system ?
W
You have to boot from a live system, either on USB stick or on DVD, then use a terminal session there.
How to clean up is outside of my knowledge, so someone else will need to guide you with the specifics on that.
But if I take a stab at it, according what Google returns for a search on
kernel blacklist in GRUB
in /etc/default/grub, add or modify the following line to include nouveau, i.e. (critical edit)
GRUB_CMDLINE_LINUX="blacklist=nouveau"
Then run "update-grub".
That will suppress the offending kernel module and let you get past that breakdown point.
Tried. Can't access the drive. Says can't be mounted.
You will need to create a mount point to mount the drive.
The live session should be able to provide the information (i.e. /dev/sd? and partition /dev/sd?# using gparted) on where the disk is and allow you to mount the drive to manually edit what is on the drive.
What does the log file say ? Do you see anything identifying the "1 update could not ..." ? Maybe that needs to be interactive.
/var/log/unattended-upgrades/unattended-upgrades.log
I know it's a bit late, but I never perform unattended upgrades, for risk of things going off the rails without my knowing what is happening. 
If you enter "ps -ef | more" at the prompt, can you tell how far along the boot process was able to complete?
Just for the hell of it, what if you tried the following:
- /sbin/init verbose splash
If that doesn't work, what if you tried:
- /usr/sbin/lightdm
Yes Eric I tried the lightdm one and also a few other things I found on the web (using another box) - no result.
So, I got fed-up and re-installed all anew with 24.10 on my laptop; trowing by the window any effort to work around a solution. I know we won't get to the solution that way - but no choice (and time - reinstall of everything all done within less then 2 hours) on a production instrument for work.
Your help very appreciated. The traces it leaves here, useful for others.
p.s. (1) it also seems (so far) that the reinstall did solve the memory issue raised in another post here. Again without knowing what really did happen in the background.
W
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All good! Main thing is your issue is resolved. Hopefully you won't see it again on another machine. 
1 Like
I, too, had a 24.04 to 24.10 upgrade where LightDM repeatedly rebooted before logging in.
The release notes state the following.
“Switched back to Slick Greeter (replacing Arctica Greeter) due to race-condition in the boot process which results in the display manager failing to initialise.”
So I looked in /etc/lightdm/lightdm.conf.d/ and there was no Slick Greeter setting.
However, 90-arctica-greeter.conf was still there.
I opened 90-arctica-greeter.conf with a text editor and modified greeter-session=arctica-greeter to greeter-session=slick-greeter and it worked fine.
I suspect this is due to Slick Greeter not being configured during the upgrade.
2 Likes
Why are you not using **Ubuntu 24.04.1 LTS?
Hi, @hirotyan and welcome to the Ubuntu MATE Community!