Got issues after kubuntu version upgrade from 20.10 to 21.04

After I followed this guide enter link description here I got several issues:

  • Grub error on startup: cannot find command 'hwmatch'
  • Okular stopped opening .epub books - just freezes until I kill the process
  • Fps drop for many games on steam (got 15-30 fps in Killing Floor 2)

Now I added mesa driver and Okular opens .epub books again, but games on steam are still have very low fps

What could be the reason for that?


The reason why you may have gotten issues after an upgrade is because upgrading a linux system is not obvious. Depending on the current configuration of a user, updates may involve some issues or inconsistencies, causing usually small, but sometimes more important issues.

In many cases, such issues can be solved with some technical knowledge. However, lacking technical effort or the time/resources to find solutions, the best recommendation is to do a fresh install instead, and reconfigure the system after the installation. A fresh install will cause an optimal configuration as implemented by the Ubuntu developers, that only needs to account for the hardware, and not for a previous existing installation.

A fresh install of Ubuntu takes 20-30 minutes. With some configuration, you will essentially be up and running again in about an hour. You will have a system that is thoroughly cleaned from old applications and old configuration.

If you would rather want to attempt solving the issues, and want to seek help, then feel free to open a specific question on this site, with a title directly referring to the specific problem, and with adequate system information.