I have been having a weird problem recently where demos won't play. They used but now they won't.

If I try to play a demo, it gives me these errors:

nknown command "cl_thirdperson"
C_GameInstructor::ReadSaveData failed to read GI.lesson.Swap_Split_Screen_Control
] playdemo blademo
Playing demo from bla.dem

Host_Error: CMapLoadHelper::Init, unable to open maps/workshop/559848462336801621/1367724875.bsp

If I try it again, the game crashes.

Probably because you don't have the map. I'm not sure.

you need the exact map that the demo was recorded on, in the same folder

Oh well...I found that I actually deleted the map and then redownloaded it. -.-