Files Not Recovered: The Device is Not Ready

I am trying to recover some files off an external hard drive. I had thought I had recovered all the ones I needed a few weeks ago, not realizing that picture file extensions .NEF, .DNG and a few others do not scan when you pick "Pictures". Not knowing this, I reformatted the drive, only to discover later that I was missing about 15k files

I rescanned the drive with Recuva for ALL FILES and I got a result that showed something like 83k files (See attached file Recuva1 for a screen shot) I tried to recover but keep getting an error message saying "Files Not Recovered with a reason of "The Device is not Ready" (see attached pic "Recuva2" What does this mean and what am I doing wrong?

Recuva1.JPG

Recuva2.JPG

Hello, I am having the same issue. Were you able to resolve? Thanks!