Apple is recalling a batch of 1TB Seagate drives shipped with 21.5″/27″ iMacs manufactured between May 2011 and July 2011. The recalled drives “may fail under certain conditions”.

If you purchased one of these affected iMacs, and registered it with a valid email address, Apple will be contacting you regarding the drive replacement. Alternatively you can visit this site, enter your serial number, and see if your iMac needs to be serviced: http://www.apple.com/support/imac-harddrive/