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You explain 8 ways to sunday how to replace the hard drive. However, I can’t find anywhere on your site where to get the new hard drive and what sizes are available and if there any upgrades. Thanks.
Well… It’s complicated ;-} The Mid 2011 systems onwards which use 3.5" drives require a 3rd party external thermal sensor in order to use non-Apple drives. Here is the adapter you’ll need in addition of the SATA drive: OWC In-line Digital Thermal Sensor for iMac 2011 Hard Drive Upgrade And to help you here, here’s a listing of 3.5" drives that will work: https://www.ifixit.com/Store/Mac/iMac-21...]=on