Hello, I just bought used Mac mini 2012 from the ebay. Everything works fine, it has great specs (i7, 16GB RAM, 240GB+1TB Fusion Drive...), but........when I started it for the first time, I immediately installed update on High Sierra, so I don't know how boot was going on Sierra actually. But on HS, the progress bar under apple logo is loading like for 5 minutes approximately. First half of the progress bar is loaded in few seconds, next is the hell. Do you know, what could possibly help, to fix this issue or determine what's the issue here? I already ran disk checking (I mean that thing in Disk Utility to save your disk or something...)..it was doing something, but it didn't help. Thank you. PS: The user logging and speed of disk itself when logged in is just great.