Apple has released a firmware update for its MacBook Air systems, which addresses a problem with the SSD drives on these systems that could lead to data loss. Apple apparently issued a small batch of faulty drives with its mid-2012 MacBook Air, and this firmware update should correct the problem.
The update should be available via Software Update for relevant systems, and being that this addresses a potential data loss issue, this update is highly recommended. If you do not see the update available in Software Update, but believe your system is an affected one (mid-2012 MacBook Air), then you can download the update from the Apple Support Web site and run it manually.
When you run the update manually, it will test your system to determine if the update is needed, and then apply it if the faulty SSD is found. If your system does not need the update, then the updater will not continue installing.
If the updater cannot update your drive, then on its update page Apple claims you can make an appointment to have the SSD replaced, free of charge.
The firmware update is a small 2.21MB download, and requires OS X 10.7.5 or OS X 10.8.3 or later to install. As always, be sure to fully back up your system before applying this update, and also be sure to plug your system into a reliable AC power outlet and follow the on-screen instructions for applying the update. Firmware updates sometimes require the system to restart at least a couple of times, and there may be a significant pause between automatic restarts of the system, so be sure to allow the updater to run its course uninterrupted.