Apple Inc. released Battery Update 1.4, an update that, "improves the ability of MacBook batteries to maintain a charge when the system is shut down and not used for an extended period of time."
If you have a MacBook, you can find the update in Software Update, or you can visit Apple's support site for a download page, as well as a page that offers users additional information and step-by-steps instructions for installing the update.
Apple provided a lis of the specific MacBook models that are affected by this update:
- MacBook (13-inch)
- MacBook (13-inch Mid 2007)
- MacBook (13-inch Late 2006)
- MacBook (13-inch Late 2007)
- MacBook (13-inch, Early 2008)
- MacBook (13-inch, Early 2009)
- MacBook (13-inch, Late 2008)

Bryan Chaffin
11” MacBook Air 1.6GHz dual-core Intel Core i5: $829.00 Delivered
Samsung S22B300B 21.5” LED Backlit LCD Monitor: $129.99 Delivered
Canon imageCLASS Monochrome Multifunction Laser Printer: $129.99 Delivered

What’s this “not used for an extended period” thing about? To me, that would be like two days.