Valve has said sorry after thousands of Steam accounts for Call of Duty: Modern Warfare 2 were banned for no reason.

President of Valve Gabe Newell has written to everyone who was banned to say he is terribly sorry. "This was our mistake, and I apologize for any frustration or angst it may have caused you," he said.

The problem was that Steam would fail a signature check between the disk version of a DLL and a latent memory version. Newell said that this was caused by a combination of conditions occurring while Steam was updating the disk image of a game.

Fortunately Steam software makes it possible to to manage and reverse these erroneous bans and it has done so. Those who have been deleted have been given a copy of  Left 4 Dead 2 to play and give as a gift on Steam.