Hello, I am using LR Classic 11.3.1 on a 16" macbook pro. I have a collection of 477 photos (some RAW, some tiff and some jpeg). If i select about 150 and hit Play LR shows a stau bar and says something like "preparing" and eventually the slideshow will usually run. If I select all 477 photos LR "prepares" and the status bar moves along and when it gets to photo477 I get a spinning ball for several minutes and then the status bar disappears and nothing happens. I eventually hit play and the entire process starts over.