Shader cache keeps getting deleted

Hey,
This league my game crashes from time to time and every time this happens, my shader cache seems to get deleted, because right after I load it up again and go into a map, the shader bar is up all the time and my frame rate is almost at 0. This lasts for quite a while, until the cache is loaded up. Then the game runs more smoothly, until the whole process repeats. This also seems to happen sometimes when I just restart the game without it crashing, but not too often.