a game which plays fine in the editor without error in the console won’t play or crash as a built player, any explanation ? what’s the methodology to debug ?
Keep console.log in /Applications/Utilities/Console.app open and wait for it to crash. Then check out what gets printed and fix whatever errors there are. 
There could be an issue for instance if you’re doing GetPixels on something that gets DXT compressed only when you actually made a build.
It could be something more strange and an actual Unity bug, but I kind of doubt it.
Cheers,
-Jon