Chosen Solution

I have replaced the HDD of my iMac by a 1T WD Blue SSD, but the computer is not recognizing the SSD. I booted from a live linux CD and the drive is not showing up on for instance lsblk. Any help would be greatly appreciated.

This is the problem with the Fixed III SSDs in SATA II Macs like this - they do not work! You need a drive with a SATA II mode, or a Fixed II SSD. As to what drives I’d recommend there are two: OWC Mercury Electra 3G (500GB)OWC Mercury Electra 3G (1TB)Samsung 860 EVO