Cubase 9.5.21 System Freeze!

I downloaded and installed Cubase 9.5.21 the other day and was using it today for a while. I then opened up a project and went to change the color of one of the tracks, when not only Cubase froze up, but the entire computer completely froze and had to be force shutdown. I honestly have not only never seen this in Cubase before, but never seen this happen on a Mac computer before. Usually if a program like Cubase has an issue, it will just crash and not effect the system. Keep in mind that Cubase was not even running or playing anything back a the time. I simply selected a track and changed the color of it. Not sure if this is a problem with 9.5.21, but I am going to roll back to 9.5.1 for now and see, since its never happened before until right after updating Cubase today to the latest version.I;m on a Mac Pro, mid-2012, 3.2GHz Quad-core, OSX 10.13.3 (does not give OSX 10.13.x High-Sierra option in the above selection for some reason).

Did this happen more than once? It could have been a one time thing.

ii thought id post here
Cubase pro 9.5 running on a mac high sierra keeps crashing as soon as i try to save any audio recording
i updated to 9.5.3 saw on a forum it was common on this version so went back to 9.5.21
still happening…literally as soon as i try to save any audio recording
any help?
iv uninstalled and reinstalled twice (cleared all files also)