When I play around in Kicads simul and it goes into a loop - because I have no idea what I am doing - the whole Kicad gotta go, since it is just one binary. Is the latter the future? Can it be worked around? Sure, nowadays with SSD:s it’s quickly back on track, but I sometimes lose changes.
/Mikael
A few years ago, the Schematic and PCB editors (and Symbol and Footprint editors too I think) were all separate programs, and people with more programming experience then me decided to integrate them because it was a lot easier for those programs to communicate with each other.
I found this quite sad, exactly because of your case. If one application crashes, the whole bunch crashes now. But because it was a deliberate choice of the developers to go in this direction, it is unlikely to change again.
It may be relatively easy for the KiCad developers to put a big exception around each of the (previously separate) program parts, and then give the user at least an option to save files and do a more graceful exit. But possibly something similar is already implemented. KiCad makes automatic backups, and it may make such an automatic backup when it crashes, but I would have to force a crash to test this.
The 7.99 nightly development version has a stop button to cancel the simulation when it is unreasonably long and you don’t want to wait for it to complete.
There are probably still situations when you need to kill the process anyway, but at least for some “simple” cases the stop button might help.