Yes! Deleting preferences seems to be the answer. So far things are looking like and working like they should. If not, I'll check back in a few days.  The reports of empty tabs are easy to find online like here:  https://quickbooks.intuit.com/learn-support/en-us/other-questions/compatibility-with-new-mac-os-vent... 

I'm hopeful this fix does the trick. Thank you.