Last Updated: 2021-05-16
I upgraded from macOS Mojave to macOS Catarina. This new version used 64-bit for many (all?) programs. As a result, the drivers for my expensive audio interface (M-Audio Quad) broke and the manufacturer said they would not release any upgrades for quite some time.
This was especially annoying because I invited people over for to play using these equiqment the next day.
Before upgrading, I should have looked up whether all the hardware I used (monitor/mic/keyboard/mouse) supported the latest OS version. Ditto for the core software I used.
Before upgrading OS, check that both your software AND hardware is supported