Dorico crashing when changing mode

I frequently get Dorico crashing when changing mode - through various versions of Dorico up to the current one.
After importing an xml file, I copy all parts into a new Dorico file so it’s ‘clean’.
Then I delete any extra players and parts that Dorico has created in Setup Mode.
I have learnt to save the file at this point.
When I now change to Write mode I get these frequent crashes.
I attach Diagnostic reports for just before, after the crash and also the Mac OS report in case it’s of any help.
It’s not a big deal since I have saved all the work up till that moment.
Dorico (1.4 MB)
Dorico (1.4 MB)
Mac OS (26.7 KB)

Thanks for submitting the crash report. It’s an odd one: an exception is being thrown because Dorico is trying to access an element in a container that’s out of range, but it’s really not clear what is causing that to happen. If you have a set of steps that can reliably (or reasonably reliably) reproduce the problem with a particular set of MusicXML files and projects, please let us have them so that we can investigate further.

Is it possible that you were viewing one of the parts that you have deleted, before you deleted them? It might be that when you return to Write mode Dorico is somehow trying to reinstate a view of a part that no longer exists, although that oughtn’t to be possible.

So far it is refusing to crash but I will keep trying!

No, it was open at Full Score.

I still get the odd crash - but I cannot get it to repeat.
I have loaded earlier files from the Dorico backups for the same project - but then it will NOT crash again.
Perhaps my computer is getting too old and is struggling sometimes (depending on what other processes may be going on). I notice that deleting a Player seems to take around 5-8 seconds.
It is late 2012 iMac; OS Catalina 10.15.7; 2.9Ghz i5; 16Mb RAM

If you are getting the occasional crash, there should be crash logs: please do Help > Create Diagnostic Report and attach the resulting zip file here.