Apple today issued the first update for Leopard, its three-week-old operating system. The update fixes a wide range of out-the-gate bugs and patch three security vulnerabilities.

The update to Mac OS X 10.5.1 includes changes to a host of Leopard features, including some that have given early adopters fits, such as a gaffe that cripples , some software, including Skype, when the firewall is set to the most flexible option. It also tackles problems formatting drives before they can be used with Time Machine, the integrated backup and restore software.

Other non-security fixes address a file copy bug that deleted data if the destination drive suddenly went offline during the job, and boost the reliability of iCal in delivering alarms via e-mail.

Apple also released the first security patches for Leopard as part of 10.5.1, quashing three bugs in the firewall. None of the vulnerabilities could be used by attackers to execute code remotely, but two of the trio expose the Mac to probes. The fixes close those holes.

Mac OS X 10.5.1 can be downloaded from the Apple Web site or retrieved using Leopard's built-in Software Update feature.