On Ubuntu Studio 18.04 and 18.10 I had a problem with Harrison Mixbus version 5 and 5.1 (new update). Harrison Mixbus crashes during the the starting phase, after selecting the Jack driver. Which is strange as Ardour 5.x seems to work fine.
After reading some help pages I found out that there is a suspicious file called ‘csladspa.so’. If you find yourself in a simular situation, you might want to try the following…
Rename the suspicious file called ‘csladspa.so’, located in /usr/lib/ladspa/csladspa.so, by opening a terminal window and enter the following command:
sudo mv /usr/lib/ladspa/csladspa.so /usr/lib/ladspa/csladspa.old
Now try to start Harrison Mixbus again!
If this works for you, you might want to try remove the package called “csladspa”. You can uninstall “csladspa” in the terminal window by issueing the command ‘sudo dpkg -P csladspa’