This comes up rarely. It usually has to do with Premiere Elements struggling with creating the real time previews used in editing. There have been two causes. First is that the preview needs to be "rendered". There is a button on the screen or you can press enter. Second is that the video file uses a codec (like MJPEG) that won't work with Premiere Elements.
A
Anonymous
October 1, 2019
Solved
A
Anonymous
October 1, 2019
but no effect. I also tried installing Premiere on another computer, but the problem remains.