My Mac Build doesn't Work

I'm pretty new to unity, and I made a build for my game (its not a very complicated game, only 4 levels). I made it on a mac, and when I played it on my computer, it was fine, but I tried uploading it to google docs, and if I download it from there, it says "You can't open [name of game] because the classic environment is no longer supported." I tried deleting the file and rebuilding it, but it says the same thing every time. What should I do?