Originally Posted By: plantsower
I didn't erase anything yet, but I went into the ext. HD and ran disk utility, I took screen shots. The weird thing is that when I ran it on Mavericks it said it was repairing it and at the end it said it was fine. I clicked on Mavericks after that and still got the blank screen with the circle and line. In Sierra 2015 it said it was corrupted, but it never said it was repairing it but that it needed repair. Gee thanks. And on the Sierra 2012 it said it was repairing it and it was fine. Who knows?

I should have specified that in addition to running RD on each partition you need to run it on the drives themselves, i.e. the top line items in DU's sidebar that identify the drives' manufacturers.

To repair Sierra 2015 and anything else that may turn up needing repair, boot into Recovery - command-R - and search for DU. (I think it'll be under "Utilities" in your menu bar.)

I'll wait for the results from both drives before going any further.

Not that I"m terribly at all optimistic, but don't forget to try Amazon after you repair Sierra 2015.

Have you got TechTool Pro, Drive Genius, or anything of that ilk?

The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire