Apple is advising all owners of MacBooks or MacBook Pros bought after February 2006 to download a software update that will help fix some battery issues.

The update, available through Software Update in the Apple menu or here on Apple's site, was released to correct some battery performance problems, such as shorter than usual battery life or problems charging the battery, according to a Web page on the support section of Apple's site.

But if that fix doesn't work, notebook users should contact Apple to have their battery replaced if they notice the following symptoms, cut and pasted from Apple's support document:

• Battery is not recognized causing an "X" to appear in the battery icon in the Finder menu bar.
• Battery will not charge when computer is plugged into AC power.
• Battery exhibits low charge capacity/runtime when using a fully charged battery with a battery cycle count (as shown in System Profiler) of less than 300.
• Battery pack is visibly deformed.

Apple says these problems aren't safety issues, just performance-related, a relief for those who remember the massive battery recall of last year. Apple had to recall 1.8 million batteries manufactured by Sony as part of a larger recall that affected just about everyone in the PC industry.