Unespected (frequent) freeze crash with Xubuntu 20.04 LTS

Solution 1:

System "freezes" are often caused by running too many, too large programs and running out of available memory. Use free to see if you have swap space, read man mkswap swapon fstab to create some. Traditionally, swap space of 1.5 × RAM has been recommended, but YMMV. If you don't plan to hibernate your system, you can have less than 1.0 × RAM.

Solution 2:

After a "sudden shutdown", aka "system crash", and reboot, the terminal command sudo journalctl -b -1 -e will show you the end of the previous boot's log's. If there is no hint there, suspect power/ overheating.

Read man journalctl to see how to extract information from the logs.

You can find how I make use of journalctl easier at https://askubuntu.com/users/25618/waltinator. .