The 10.6.3 Update is recommended for all users running Mac OS X Snow Leopard and includes general operating system fixes that enhance the stability, compatibility, and security of your Mac, including fixes that:
- improve the reliability and compatibility of QuickTime X
- address compatibility issues with OpenGL-based applications
- address an issue that causes background message colors to display incorrectly in Mail
- resolve an issue that prevented files with the # or & characters in their names from opening in Rosetta applications
- resolve an issue that prevented files from copying to Windows file servers
- improve performance of Logic Pro 9 and Main Stage 2 when running in 64-bit mode
- improve sleep and wake reliability when using Bonjour wake on demand
- address a color issue in iMovie with HD content
- improve printing reliability
- resolve issues with recurring events in iCal when connected to an Exchange server
- improve the reliability of 3rd party USB input devices
- fix glowing, stuck, or dark pixels when viewing video from the iMac (Late 2009) built-in iSight camera
Apple Support Link