it was not stated in the system requirements that one would need a printer to use Adobe Illustrator.
By @defaultoj575640rdf9
This is a user forum. Only people labeled as "staff" work for Adobe.
Connecting a physical printer (or turning it on or updating the driver or fixing the printer) is something that has been figured out collectively in this forum and has proven to help a majority of people who report this kind of problem.
There are other causes for files failing to open. And there may be other methods to address the issue, but connecting a printer is the quickest one that has been found.
Maybe you will need to contact Customer Care and have them take a look into your system. https://helpx.adobe.com/contact.html
You haven't told us which system you use - did you update it as well? Are you perhaps on a Mac OS beta?
I was able to solve the problem with help from elsewhere: the font cache apparently got corrupted.
After typing in the terminal
sudo atsutil databases -remove
and restarting the Mac everything worked fine again.