"Warning" window after launching computer (Ubuntu 21.10)

The Error is, that Thread.isAlive() is not known by your python version, which has changed from 3.8 to 3.9 due to the upgrade. In 3.9, the attribute has been renamed to is_alive().

Seems you have a preinstalled Ubuntu from Dell, that has some software installed ("Dell Linux Assistant") that is not compatible with python 3.9.

You should either

  • ask the Dell support if they have a fix.

  • or simply try to get rid of that software, e.g.:

    sudo apt remove dell-recovery dell-linux-assistant
    
  • or (what I'd recommend) reinstall a clean Ubuntu without Dell bloatware.