Re: "Error: You need to load the kernel first"
I'm not a fan of Disk Utility. I would not trust it's claim as to disk health.
A more reliable approach (in my opinion) would be to find out the make and model of your hard drive, go to the manufacturer's website, and see if they have a drive health utility you can download.
If the drive has a warranty, they typically demand a report run from their own utilities before they will replace it.
Ubuntu 16.10 Mate, Mint 18 Mate; MS Win 8.1, MS Win10 Pro.
Will not respond to PM requests for support -- use the forums.