I've had PSE 20 on my Mac (OS 12.0.1) for less than 2 weeks. It refused to open the first day. I thought maybe the install had been interrrupted or something so I did it again. A result: the Organizer opened but nothing else did.
The next day the Welcome page opened but none of the buttons in that window responded when clicked (the Editor, the Organizer). All I got was the spinning beach ball thing. I was able to open the Editor from my Dock, tho, and the Editor worked fine. Yay!
It's opened OK 4 more times; I've had 4 more opportunities to use it. Worked well, no issues. I thought everything was OK.
Now, today, it refuses to open. NOTHING works. Lots of bouncing in the Dock, then force quits. Sometimes the icons don't even bother to bounce. They just sit there with the little "open" dot under them, looking like the thing is open but it isn't.
The Welcome page buttons do respond now, tho, except that they don't open anything. Spinning beach balls & bouncing in the Dock.
I've been using versions of PSE since 2006. They opened! They worked. No surprises, no fails.
This is disappointing, to say the least. I need the app and I can't afford to lose the money I spent on it.