This is the first time anything of the sort happens to me. I was working on my newest CSGO map, still very early in development and I decided to compile it to see if everything looked right. (It might be worth to note that this was not the first compilation of the map. There had been a bunch before this one.)
What happened is that, after compiling, CSGO opens up for a moment and then shuts down. Bringing up steam after this reveals the "Failed to start game(app already running)" error. So I open up CSGO by itself and try to open the map through the console. Again, after it starts loading the map it crashes and brings up the same error. I've tried other maps, both official maps and some I've done before and they all work fine. I've tried deleting the "appcache" folder as the official help recommends and still nothing.
I don't understand how this specific map could be causing something like this. Opening the task manager reveals that no other instance of CSGO is running, and no matter what I do, nothing seems to fix it. Worst of all is that it seems no one else on the internet has the same problem.