Chosen Solution
BACK INFO. Mac $@$* the bed one day, cant see HD in recovery mode but could see SSD I just finished replacing the HD with a brand new 4TB, I also installed the heat sensor as per recommendation. I boot into RECOVERY mode and all I still see is my SSD in disk utility If I select restore from back up or install OS it doesn’t show the new HD or the SSD SO NOW WHAT? Can I install the OS onto the SSD from a memory drive so the computer can be usable even if I cant get the HD working? ( I saw it wont let me patition the SSD, but I can erase and format it. If I do that in recovery mode wont it remove the RECOVERY mode from the SSD ?) Do I need to do the memory drive OS install to find the Hard drive? Do I need to remove the heat sensor all together? Im literally back to where I started before opening up my IMAC.
Sounds like your machine may have been formatted as a Fusion drive if it also has an SSD installed. You should be able to install OS to the 4TB HDD from a working Mac, then install drive to machine. Some of these iMacs has tiny SSDs (64GB or less) that can be safely ignored or used exclusively as Recovery drive.
