Why will an iMac 21.5" Late 2011 not accept an operating system?
crwdns2934249:0crwdne2934249:0:
I am working on a Late 2011 21.5” iMac and went to install a new Solid State Drive into the computer. After attempting to install High Sierra with the new SSD as the internal drive (and having it fail), I installed High Sierra onto the SSD externally on a separate computer and was able to successfully install the operating system onto the SSD. However when I reinstalled the SSD into the iMac, the computer did not accept the already installed operating system.
I have since installed the same SSD with the same operating system I had installed onto it into another iMac Late 2011 21.5” and that computer loads up without any issues.
Is this a hardware issue inside of the iMac or a possible firmware lock?