Apple says firmware update solves MacBook shutdowns

"The MacBook SMC Firmware Update v1.1 improves the MacBook's internal monitoring system and addresses issues with unexpected shutdowns," the Mac maker wrote in a support article on its website. "This update is recommended for all MacBook systems, including those that received warranty repair."

The Cupertino, Calif.-based company said MacBook owners may use the Software Update feature of Mac OS X or download the MacBook SMC Firmware Update v1.1 from its website.

"If your MacBook is running Mac OS X 10.4.6, you won't be able to see the SMC Update until you update to Mac OS X 10.4.8," Apple noted. "Once you have updated your system software, the SMC Update will appear as an option in Software Updates."

On the other hand, MacBooks running Mac OS X 10.4.7 will be able to download and install the SMC Update, so it is not essential that users update their system software. However, Apple always recommends updating to the latest version of the system software.

Seemingly stumped over the source of the shutdown issue until now, Apple in September began telling affected customers to contact its Apple Care support staff to arrange for their notebooks to receive hardware diagnostics and treatment.

In some instances, the company replaced the MacBook's processor heat sink and in others, the entire logic-board. However, several users who had sacrificed their relatively new notebooks to Apple's support depots for successive repairs continued to report shutdown issues.

The mounting frustration over the problem eventually came to a head earlier this month, as MacBook owners repeatedly plagued by the issue began organizing a class action lawsuit with the help of ClassAction.com.

Apple said customers who continue to experience trouble with their MacBook after applying the new firmware update, or those whose MacBook is in a state that will not allow new software installations, should contact AppleCare for further assistance.