"hl2.exe has stopped working" crash

This is a Very long running problem I have had with garrysmod, at one point it somehow stopped for a week and then started again, i do not know why.
Its a crash, but NOT RANDOM.
I can start garrys mod and go onto a server and play fine, but if I want to change servers or if the server changes map, everything loads fine until two bars are missing from the loading bars and I get the “hl2.exe has stopped working” message.
When i ask for more information it tells me that the file causing the problem is materialsystem.dll
I have verified and de-fragmented many times, but this does not help.
So can someone help me with this problem?

Thanks :slight_smile: