We gave high praise to Apple's 2012 model MacBook Air (see our review
for the full scoop), unfortunately one thing we're not able to test for is reliability over long periods of time. That's usually not an issue, but in this case, Apple is warning 2012 model MacBook Air owners that a small percentage of flash storage drives used in these laptops have an issue that might result in data loss (we didn't experience this ourselves).
Apple has issued a firmware update (version 1.1) that will let you know if your MacBook Air's storage might be affected. Unfortunately, there doesn't exist an update that will fix the problem, but if you happen to have one of the small number of wonky SSDs, Apple will replace it free of charge.
The issue affects certain 64GB and 128GB SSDs used in the previous generation of MacBook Air systems powered by Ivy Bridge and not the most recent models based on Haswell (which we also reviewed
Should you be one of the unlucky ones, Apple strongly recommends avoiding any OS system updates or new applications. Apple also says you should back up your data on a regular basis until you receive a replacement drive. For more information, visit Apple's Support Page