In that case please check whether there are any crashlogs in the macOS console app under "User Reports".
Also if possible please go to the about tab in BetterTouchTool and click the "Export Debug Information" button. This will create a folder called BetterTouchToolDebug on your desktop. Please send that to andreas@folivora.ai, then I may be able to see what causes the crash.
Thank you for this, and for replying so quickly. I have sent the Debug Information. There are about 12 crash reports for BTT showing in Console. Would you like me to send one of those too?
For future reference:
Both crashes here were caused by recursive keyboard shortcuts being setup in BTT (e.g. CMD+R triggering CMD+R will cause an endless loop unless you click the little cog icon left from the shortcut recorder field and enable "Prevent recursive triggers").