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

Steam Client

• Fixed in-game overlay causing a crash for users running Windows XP without Service Pack 2 installed
• Fixed mouse clicks in-game sometimes not registering in the correct position for the in-game overlay
• Reduced CPU usage when using chat and group chat
• Reduced CPU usage while idle on the Store and Community tabs
• Fixed Steam windows showing up in the task-bar but impossible to restore
• Fixed a regression with being unable to minimize windows by clicking their taskbar entry
• Added new driver checks for Team Fortress 2 on Vista and XP
• Fixed microphone being left on when leaving the settings dialog after testing it
• Fixed a rare crash on startup