Fatal Error: EXCEPTION_ACCESS_VIOLATION_WRITE / 0x0 - 7516363881

Fatal Error: EXCEPTION_ACCESS_VIOLATION_WRITE / 0x0 - 7516363881 : crashes/01fdb7a7-ba68-4129-b7b8-926f636a94f6

tried to generate a photon map in hammer

Clicked "Preview Baked Lighting" -> "Bake All Lighting" in Hammer. VRAD progress shows up and then the crash triggers (Hammer and s&box editor stay open though, only the baking crashes)