Late on Friday, Apple released a software update designed to fix performance of MacBook and MacBook Pro batteries.

But additional statements from Apple since that release have been a little more forthcoming. If the update doesn’t fix your battery, Apple may be willing to send you a free replacement, even if the computer is out of warranty.

The qualifying symptoms of a dead battery are:

  • 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.

Judging by the reactions in the Apple Forums, a lot of users are very pleased to see the release of this update (although a few have reported problems after installing it). It’s fair to say that battery performance, and stories of warping batteries, have been a problem for Apple for some time now. Some action to remedy the situation is welcome, although some sufferers of swollen batteries might wish it had happened sooner. Don’t forget, though, that there was a previous MacBook Pro battery recall in July last year, so it’s possible that some users will be getting a second replacement battery as a result of this new offer.

Personally speaking, the battery horror stories I kept reading were one of the main factors that stopped me buying a replacement portable computer earlier this year.