Boot into a previous version of Ubuntu to fix startup freeze
If your Ubuntu installation locks up as the graphical boot screen attempts to initialize, and you can't get access to your system after starting it up, booting into a previous version can be a help.
This can happen after updating to the the latest update to Linux 4.4.0-108 kernel, which included a fix for the Meltdown vulnerability.
You should be able get back into Ubuntu again by going back to the previous working kernel version from GRUB, in this case 4.4.0-104-generic:
- Reboot while holding down the Shift-key
- Select Advanced options (second option) and hit Enter
- Select 4.4.0-104-generic (third option) and hit Enter
The reason I include the position in the list is because my monitor has a huge resolution, making the text unreadable.
How to see your versions of CPU, Ubuntu and kernel:
$ cat /proc/cpuinfo
model name : Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz
$ lsb_release -a
Description: Ubuntu 16.04.3 LTS
$ uname -a
Linux comp 4.4.0-104-generic #127-Ubuntu SMP Mon Dec 11 11:16:42 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
EDIT: A new Ubuntu release has just been issued, so updating your system should result in kernel 4.4.0-109 getting installed, which seems to work for most people: