'hl2.exe has stopped working' when I run demos

I am trying to record GMod demos, and play back videos of them. But when I try this using in-game tools (by pressing Esc, clicking Demos, and press play), all I get is the video playing for 2 seconds, freezing, and the error 'hl2.exe has stopped working'.
Can someone tell me why this happens, and what I need to do to fix it?
Best Answer
Well, if you recorded them on YOUR system, they should be saved in the Garry's Mod demos directory:
C:/programfiles/steam(or valve)/steamapps/<Username>/garrysmod/garrysmod/(demos folder)/(name of the demo)
Or on an Apple iMac:
~/library/Application Support/Steam/steamapps/common/garrysmod/garrysmod/(demosfolder)/(name of the demo)
And for you few on Linux, I am not too familiar, but I imagine it should be about the same as the other two.
In each of those directories, there should be a demos folder named something like demos
or possibly recordings
and from those folders, you can find your recorded demos and play them or do whatever.
Pictures about "'hl2.exe has stopped working' when I run demos"



Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Andrea Piacquadio, Ketut Subiyanto, George Becker, Andrea Piacquadio