Valve's Erik Johnson made a post about a start-up bug on
Shacknews. Thanks Frans:
For people that
are running into the bug on startup that looks like:
"Map Version is 0, expecting 19"
Try this to see if it works:
1. Go into your \Steam\SteamApps folder.
2. Rename the file called sourcemodels.gcf to something else.
3. Relaunch the game.
This is going to require a redownload of this file, but if you want to get
playing tonight it's probably the best path. There are a couple of people now
that were in this situation that were fixed this way.
As soon as we possible we'll release a fix for this that will not require this
Please let me know if this does or does not fix this specific problem for you.
Just shoot me an e-mail at
firstname.lastname@example.org. If this does fix it, it would be useful to get
copies of a couple of the renamed (bad) cache files.