Apple released another beta of OS X 10.8.1 Mountain Lion to developers today, less than a week after their initial build. The beta bears a build number of 12B17, lists no known issues, and weights in at just 43.27MB (for the delta update).
The rapid release of a second beta suggests that Apple is likely preparing to release the update to users in the near future. The update is likely to contain a number of bug fixes and improvements following feedback received after the release of Mountain Lion last month.
Apple has asked developers to focus on Active Directory, iCal, Microsoft Exchange in Mail, PAC proxies in Safari, SMB, USB, and WiFi and audio when connected to an Apple Thunderbolt Display.