According to the release notes, OS X 10.8.1 includes fixes to improve the stability and compatibility of your Mac.
Here’s the list of fixes and improvements:
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.