I have late 2012 mac mini with an i5, 4 GB of ram and the standard 500GB HDD. The system had really slowed down do I decided to upgrade to and SSD drive. I cloned the current drive using CarbonCloner. I bought a crucial 275GB SSD and cloned the HDD using CarbonCloner. I think I did everything correctly, however I just can't boot from the new SSD when it is installed in the internal drive bay. I don't know why, the scenarios 1. I can boot from the new SSD when connected via USB 2. I can boot to the existing HDD when it is connected in the drive bay 3. I can read the SSD when I boot from the current HDD via USD 4. I just can't boot via the SSD when it is connected in the internal drive bay. - I don't get any errors. I just get the boot black boot screen with the apple logo and the B&W slider and it just does not complete booting. I have waited for 12 hours to complete this but after getting to about half the way, it will just get stuck not progress. Is there anything I am doing wrong. How do I fix this?