Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
Even Apple Is Not Perfect , Seagate Hard Drive Recall
Apple has started sending emails to customers about hard drive recall, called the iMac 1TB Seagate Hard Drive Replacement Program:
The Company has found out that a number of Seagate 1TB hard drives used in 21.5-inch and 27-inch iMac systems, may fail under certain conditions. These systems were sold between May 2011 and July 2011. An Authorized Service Provider (AASP) will replace affected hard drives free of charge.
Apple is contacting affected iMac owners who provided a valid email address during the product registration process to let them know about this program. If you have not been emailed or did not enter an email address on purchase , but think you have a 1TB Seagate hard drive which may be effected , you can enter your serial number HERE to see if it’s part of this program.
Owners are encouraged, with affected computers, to go to an Apple Retail Store, an Authorized Service Provider or contact 800-APL-CARE.
Apple will replace affected Seagate hard drives, free of charge, until July 23rd, 2012. Apple will continue to evaluate service data and will provide further extensions to this program as needed.
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