Random Crash? What happened?

Ok so i was playing Black Mesa (Steam version) in the middle of Surface Tension, when you go into the pipe after defeating the helicopter, when I hit a loading screen so i went to go do something real quick when i came back it was loaded and when i moved like one step I get the engine error CUtlStreamBuffer::Close() Write (null) failed 21854 != 74881 What happened? I also can’t find any crash files for it :confused:

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.