OSX が10.8.1 へアップデートです。
アップデートの詳細は下記に。

About OS X Mountain Lion Update v10.8.1
This update includes general operating system fixes that improve the stability and compatibility of your Mac, including fixes that:

• Resolve 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
• Resolve an issue that could prevent iMessages from being sent
• Address an issue that could cause the system to become unresponsive when using Pinyin input
• Resolve an issue when connecting to SMB servers with long names
• Address a issue that may prevent Safari from launching when using a Proxy Automatic Configuration (PAC) file
• Improve 802.1X authentication with Active Directory credentials.

OS X Mountain Lion Update v10.8.1 http://bit.ly/MPHCp8

AppStore 越しのアップデートは楽でいいですね、ホント。
でも念のためアップデートは電源のある場所でどうぞ。

BUFFALO Mac用増設メモリ PC3-10600(DDR3-1333) 4GB×2枚組 A3N1333-4GX2/E