no need to make multiple posts when you mac crashes.
did mac os crash ? or did sketchup ? did you get a sketchup bugsplat when booting up after that ?
did you try turning off the new engine to see if it crashes in the old one ?
I haven’t made a file bigger than 100mb, come to think of it, I don’t think I’ve ever been above 60.
150mb isn’t a small file, it’s either a file full of geometry (million and million of lines) or a file with heavy textures.
in both cases, if you don’t share a file, we can’t check it and see if it’s the cause