If you own one of Apple's latest laptops, your version of Mac OS X may not have shipped with journaling turned on (you can check by launching Disk Utility, selecting your boot volume name, and looking at the Format line in the disk information area at the bottom of the window). Journaling is a system-level feature that causes the system to log all disk changes in order to prevent data loss in the event of a crash or power outage. (When you erase a Mac volume under Panther or Tiger, the recommended option is to format it as "Mac OS Extended (Journaled)".) To remedy this situation, Apple has released MacBook, MacBook Pro Software Update 1.0, a 200K download that applies to MacBook (13-inch Mid 2007) and MacBook Pro (2.2/2.4 GHz Mid 2007) models. After you install the update, Apple recommends running Disk Utility from another startup disk (such as the Mac OS X Install or Restore disc) and performing a disk verification.