Apple has released a significant update to its Mac OS X operating system that fixes a number of significant bugs, including a widely reported video flaw in new Intel-based Macs and a VPN incompatibility with Cisco servers.

The update, numbered 10.4.5, was released on Wednesday and is aimed at PCs and servers based on PowerPC and Intel processors. Users can update via Apple's website or through the operating system's auto-update feature.

One of the most high-profile fixes involves video playback in Front Row on newly released Intel-based Macs. A number of Web sites reported that some video displayed distortions such as horizontal lines when played by Front Row, though the same files might be glitch-free when displayed in other players.

Apple introduced the first Intel Macs, iMacs and MacBooks based on Intel's dual core Core Duo, last month after announcing the switch in mid-2005. Professional users are expected to hold off purchasing the new hardware until applications such as Photoshop are available in versions that can run natively on the Intel hardware. In the meantime, PowerPC-based software runs on Intel via software called Rosetta.

This week's update also targets some Rosetta problems. One bug stopped applications using Rosetta on Intel-based Macs from successfully opening files located via an Open window's "search" field. Another problem meant the same applications didn't correctly receive notifications from Keychain, which manages authentication.

Several networking issues are addressed in the update, for instance an incompatibility between Apple's IPSec VPN client and Cisco servers.

The update fixes a flaw that caused the Safari browser to quit when deleting AOL mail messages via AOL webmail, and a bug that meant users couldn't sync with an iDisk larger than 4GB. Other networking bugs involved the copying of Portable Home Directories and use of Epson printers via AirPort Extreme.

Other fixes affect the system process "configd", streaming media viewed behind a firewall, iMovie HD, iMovie '06, an Intel installation problem with Telestream Flip4Mac, widgets, RSS Visualizer and other components.