As an educator, I do lots of screen recordings with my Quicktime application, and then edit the screen shot with an audio track I record with an external recorder and lav mic. When I import these into PP and sync everything up, all is well. I have to end up resizing the footage to 1920 x 1080 and scaling the footage to fit. (The original screen recording is an off size, somewhere around 3360 x 2100. I import to a timeline, then resize the Timeline settings and scale the footage down.) I can make cuts, ripple delete, add transitions where I need to. It all works well until I get to the end and try to puts simple Video and Audio transition to cross disolve/cross fade out of the clips. It freezes up if I try to extend the transitions or simply play the end of the clip to check everything.
I am using a Mac book pro, running 10.15.6, and PP is up to date. Any suggestions are appreciated.