On Steam for Mac, you may have been unable to start Steam games or Steam may have taken long to launch games on startup. Here is a solution.
My issue arrived with a fresh install of OSX and a fresh install of Steam. I noticed that Steam took insanely long to load. This was definitely not due to any connection or performance limitations as I have a laptop which plays Steam very well.
Eventually, after about 20 minutes when Steam launched, I downloaded CounterStrike:GO and proceeded to launch it. Steam then stopped responding and there was no indication that the game was pending launch. I would then have to force quit both Steam and the game and try again.
Check your hardware devices
Strangely enough, having devices such as a webcam, mouse, keyboard and others, affect the startup time for Steam. I found that having my Logitech mouse plugged in made Steam take over 10 minutes to load at the login screen.
Ever since the infamous ‘Steam commons folder update’, many users have complained about issues with launching games and broken folders. For me however, it’s simply been my games not launching and steam crashing.
For this method, try ‘verifying game cache’ in steam. You can do this by right-clicking the game in question and going to its properties, then clicking on the ‘Local Files’ tab and finally, ‘Verify integrity of game cache’.