Re: Can't launch the game. "Missing executable"

For me the resolution in the end was to do a clean reinstallation of Steam.
Steam "Check for updates" claimed it was, but in my steam Suport ticket a different Steam build was stated as newer.

Important

Move the "steamapps" folder outside bevore uninstalling it, since thats were all Games are stored and re-downloading can be a chore.
(Just move the contents back wile steam is down and it should find them all again. Although you might have some problems with missing icons.)