Apple has released OS X Mountain Lion 10.8.1, and the update is now available in the Mac App Store under the Updates tab. A manual installer is also available for download.

In the support notes about the update, Apple recommends backing up your system before running the installer. A reboot is required in order to complete the update.

The update includes a number of fixes:

• Resolves an issue that may cause Migration Assistant to unexpectedly quit
• Improve compatibility when connecting to a Microsoft Exchange server in Mail
• Address an issue playing audio through a Thunderbolt display
• Resolves an issue that could prevent iMessages from being sent
• Addresses an issue that could cause the system to become unresponsive when using Pinyin input
• Resolves an issue when connecting to SMB servers with long names
• Addresses a issue that may prevent Safari from launching when using a Proxy Automatic Configuration (PAC) file
• Improves 802.1X authentication with Active Directory credentials

If you are updating today (and please back up first!) let us know your results. Last week, we rounded up our top Mountain Lion gripes; hopefully some of them were addressed in this update.