CS:GO can crash when loading the next map if you're on a 32-bit operating system. To address this, you'll need to edit a txt file.
The crash is caused by going over 4GB total memory usage, which isn't possible for a 32-bit OS. To fix it:
See the official Steam support page here
If you get this error message without have used any 3rd party applications, this quick fix should solve your issue.
Before joining a server, set your resolution in-game down to the next lowest setting (e.g, if you're running 1920x1080, go down to 1776x?). Once you get in, set your game resolution back to whatever you normally use. You don't need to use this workaround again until you restart the game. There are permanent fixes, but they vary greatly and each seems to work for only a couple people. This fix seems to work for almost everybody with this particular error, however, so try this before anything else. <Somebody please edit this and give it the usual format for this wiki, I'm unfamiliar with this site but recently heard about it, a ton of people are having this issue on the CS:GO forums and this workaround isn't being spread around hardly at all! And nobody's made a real fix yet, I don't think. Have a nice day!
None - Opt out of all beta programs
C:\Program Files (x86)\Steam\bin\Steamservice.exe /Install
Help & Options
Enable Developer Console (~)
Set Launch Options...
The console will now open when the game launches.