Error verifying Steam user ID ticket?

If you ever had problems with your Steam user ID ticket, you should try these tips to solve it:

• Restart steam. Close the stream from the tray, and run your game again.
• Log out of steam, then log back in. Try your game again.
• Close steam. Go Program Files then find ClientRegistry.blob in your steam directory* and delete it. Restart steam.
• Close steam. Then update your system clock and start up steam again.
• Email steam / valve tech support, or go leave a post on their forums.

* That directory would look something like this: C:\Program Files\Valve\Steam\...