How to fix CS2 black screen on fullscreen start on Mac
Sometimes when you launch cs2 what may happen is that will go black screen regardless but don't worry just reopen it and when the valve logo appears just click it 4-5 times quick and all will be ok.
Sorry for the bad English.
Hope this works for you, I searched this fix a lot and I never found it on forums on YouTube, and I think its much needed.