This project was working fine on Friday though I'd just migrated to a new Mac. Today, every time I open the project and hit to play anything from the timeline or the program window PP crashes. It can play video in the source window ok.
I'm running Big Sur 11.2.3. I have 3.6GHz 10 Core Intel Core i9 processor, 65GB memory and AMD Radeon Pro 5700 XT 16GB graphics card.