This firmware update is recommended for MacBook Air (mid 2012) models.

Apple has discovered that a small percentage of flash storage drives in these MacBook Air models have an issue that may result in data loss. This update tests your drive and, in the majority of cases, installs new firmware to resolve the issue. If your drive cannot be updated, Apple will replace it, free of charge.

Note: If you applied this update on OS X Lion v10.7.5 and are using File Vault, the firmware will not update even though you saw a dialog box that told you it was successful. If this happened, download the update, turn File Vault off (from the Apple menu, select System Preferences, click on Security & Privacy, click on the File Vault tab, then turn File Vault off. This process can take some time). Run the update again allowing it to inspect your flash storage drive to install the firmware. Upon successful completion, no further action is necessary.

If your drive cannot be updated, contact AppleCare for service.