There are several reports that Bisq is failing with the latest Ubuntu updates.
Seems that it is a problem Linux devs are working on:
https://e2e.ti.com/support/development_tools/code_composer_studio/f/81/t/604599
https://e2e.ti.com/support/development_tools/code_composer_studio/f/81/t/604509
Here are some hints how to revert to the old Ubuntu Kernel version:
https://forum.bisq.io/t/bitsquare-dont-opens-ubuntu-16-04/2312
Do a backup of the data directory and try to run on another machine if you cannot/will not revert the Ubuntu update.
The data folder is at: {USER}/.local/share/Bitsquare