Apple on Friday officially kicked off a hard drive replacement program for specific models of its 27-inch iMac. If you purchased the computer between December 2012 and September 2013, it’s possible that your computer has a 3TB hard drive that will fail “under certain conditions,” Apple said, noting that a “very small number” of the drives are affected.

Still — 3TB is a lot of space, and you should probably be aware of the replacement program if you own that computer. It’d be a shame to lose that much data, especially since Apple says you can take it to any Apple Store or Apple Authorized Service Provider for a free hard drive replacement. Apple said it’s reaching out to folks who it suspects might be affected, and you can follow the source link below to see if your computer is in the batch.

Apple warns that, while the replacement is free, you’ll still need to reinstall your operating system and restore from a backup. You have until December 19 of this year to take advantage of the free hard drive replacement or “three years from its original date of sale, whichever provides longer coverage for you,” Apple said.