After every patch, game is broken ("Cannot initialize DirectInput. (Direct 8 required)")

[zeitdruck 0]

Whenever a patch is released, I get the error message above when trying to start the game.
So far, my only solution is downloading the game again. Verifying the integrity of the game cache via steam does not help (is done successfully, however, the problem remains). Steam is run as administrator. Updated graphic drivers/direct x/reinstalled direct x8 to no avail. Teamspeak overlays, such as overwolf might cause this issue. However, this should not be the case here, since I do not have overwolf (had it installed, but deinstalled it).  

 

Many thanks for any input.