A Steam client update is now available. To apply the update, click the File menu inside of Steam and then select "Check for Steam Client Updates...". The specific changes include:

Steam Client

• Improved in-game overlay compatibility with Kaspersky Anti-Virus
  
• Fixed potential crash when launching a game and having a large chat history
  
• Fixed error in client auto-updater which would incorrectly detect Steam already running, and then fail to update