Updates to the Steam Client and the Half-Life 1: Engine have been released. The updates will be applied automatically when your Steam client is restarted. The specific changes include:

Steam Client

• Enabled territory specific game content changes to Half-Life 1: Source purchases activated after Sept 1st

Half-Life 1: Engine

• Fixed game not loading problem in machines with more than 4GB of ram
• Fixed MOTD crash when viewing HTML pages with iframes

News Source: Steam News