[GNC] mac fails to open gnucash file

[brad]

I suddenly can't open a gnucash file (it worked recently) on Mac. 
Gnucash 4.8.   The Mac recently updated to 12.2.1, Monterey & that may 
have broken gnucash.
It will have an error msg like: 'Can't parse the 
URL/Volumes/.../brad.gnucash'
We usually run it on a Samba share, but I copied it over to the Mac and 
it can't open it on the hard drive either.   I've tried opening from 
finder, or from GC

If the answer is to update GC to 4.9 on the mac, can I keep running 4.8 
on linux and be compatible?

Thx
Brad