Apple on Thursday released an update to its Leopard operating system that's meant to fix more than 24 bugs that have troubled users since the software debuted last month.

Mac OS X 10.5.1, as the Leopard update is officially known, addresses issues affecting passwords, alerts, and partitioning, among other things. It's available through Apple's automatic download service, called Software Update.

Among the fixes: password-protected accounts now show up in the Finder's shared sidebar; disk partitioning when multiple RAID sets are created on the same disk is improved; and an issue that produces alerts when disk images are created using the Disk Utility or Terminal has been resolved.

Also patched is a glitch in which files restored in Leopard's Time Machine backup utility were not archived to the correct folders; a bug that caused To-Do lists to disappear in Apple's Smart Mailboxes; and a flaw that caused custom paper feeds to reset to 'default' when printing.

Apple has a lot riding on Leopard. It's hoping that the slick new interface that the software brings to its PCs and laptops will help it cut into Microsoft's dominance of the computer operating system market.

To that end, Leopard features a number of graphical enhancements that redefine the way users interact with their Macs. For instance, a feature called Stacks arranges all the files in a folder into an appealing fan shape when the folder is clicked.

Leopard also borrows heavily from Apple's successful iPod interface. An enhanced Finder tool lets users leaf through icons representing their files the same way they can flip through music tracks on the digital music player.

Apple is also hoping that new productivity enhancements and security tools built into the 64-bit Leopard will push it deeper into the business computing world, where the company has largely been shut out by Microsoft.