I tried to upgrade the hard drive in the 2010 mini with the corsair Neutron XT 240, and I can not get it to boot El Capitan. Cloned it, Reinstalled El Capitan from scratch, disk utility from recovery, I've tried it all. It will boot in Target mode just fine, and the mini will boot off an external drive OK as well, though it is slow - ergo the replacement. It gets all the way to the end of the progress bar, then stops. Any thoughts?