I have a 2tb mac drive that was reformatted after a bad sector. So I dd it to a win PC file
I tried DIskDoctor(trial) and it found every file in an hour or so. I test extracted a couple and they were perfect.
So I set photorec-win going on it and it started finding files (yeah!!!!)- sadly the front of the disk looks like cache folders and after 2 weeks its up to directory 140, but I note the following.
The disk is being read continuously @80M/s - about right for the drive (so its already read a couple of petabytes already - or more)
60M System and 20M photorec.exe - does it really need to continuously read like this over and over again - there is nothing wrong with the disk - and I even defragged it before starting sp at least the dd file was contig..
It is still at 0% - so looks like the universe may expire before the files are recovered.

I get the impression it tries to extract a file and writes it to disk, then changes its mind and deletes it. Almost as if it goes byte by byte and for each byte try to write out a file, see if the file is OK, if so SAVE else, try another type, with thousands of types and zillions of bytes - maybe thats why its at 0%
Ive tried cutting down the file types to just photo - but that didnt make much of a difference, and I was thinking, maybe after a while it will just speed up - but NO.
What am I doing wrong ?
Surely if DiskDOctor can find the files, photorec shouldnt be that far behind ??