Jesus - there are multiple threads about this on DUC, might be nice to combine them?
http://duc.avid.com/showthread.php?t=406401 (this one)
http://duc.avid.com/showthread.php?t=406397
I thought there was one other, must have been confused, or maybe it was already merged?
Folks opening cases - posting case numbers here would likely help.
The Mac keeps a log of what has been installed in /var/log/install.log. I expect Avid support, iLok support and any plugin vendor support are likely going to want to see that. May be a good idea to attach that log file to support requests.
I *think* Safari 13 may have been part of the update applied here, that could potentially touch a lot of underlying subsystems, libraries, etc.
You never know in these situations, did Apple break something, did they fix something? Was some plugin toolkit vendor, Pace, or Avid relying on some improper or undocumented behavior etc. or did Apple just just screw the pooch? Finding the root cause may take several vendors looking at stuff together.
Oh well folks who have backups and those who don't... maybe if you can't get stuff done because your Pro Tools system is having problems, now might be a good time to sort out doing backups. I'd go for using Carbon Copy Cloner for boot/system drive backups, a quick reboot off a clone can get you running again, possibly also backed up with TimeMachine, and possibly using TimeMachine for session backups in combination with cloud backups and off-site storage.