Apple launched a replacement program for the flash storage drives on some mid-2012 MacBook Air models. According to an Apple webpage explaining the program, the company has, "determined that certain 64GB and 128GB flash storage drives used in the previous generation of MacBook Air systems may fail."
Apple sold these systems between June of 2012 and June of 2013.
On Thursday, Apple released a firmware update to address data loss on this line of MacBook Airs, but some users were directed to the flash drive replacement program after installing the update.
According to the program's webpage, "To see if your drive may be affected, go to the Mac App Store, click on Updates and choose the MacBook Air Flash Storage Firmware Update 1.1. The firmware update will test your drive to see if it is affected. You will be directed back to this page for next steps if needed."
Users who are directed to that page are encouraged to, "not install any operating system updates or new applications," and to, "[back up] your data on a regular basis until you receive a replacement drive."