Ok I forgot the login stuff for my steam forum account so I'm posting it here because I know you guys are knowledgeable in just about everything

I just finished downloading Portal 2, but when I run the game I get just past the Valve and Source Engine logos and then I get a CTD and error message saying "Could not load library client."

Does anyone know how to fix this?

Tried verifying the game cache? Right click on the game in your Steam library -> "Properties" -> Local Files tab -> "Verify Integrity of Game Cache..."

Should take a few minutes or more depending on the size of the game and if it needs to download any additional files. If you do have some corrupt/missing files, Steam will download them for you automatically.

Okay try this: Open the task manager and make sure nothing related to Portal 2 or Steam is running, then restart steam and verify Portal 2 by going to your Game Library, right-clicking on Portal 2, selecting Properties, selecting the local files tab, then selecting Verify integrity of game cache.

No idea if it'll work, but give it a shot.

Thanks guys! That worked.

No problem. B)

Awesome! You're welcome.