Hello All,
This all happened rather suddenly, I ran Seatools' short test on this external USB drive less than a month ago and there were no errors of any kind. Yesterday I tried copying something from this drive and got a CRC error. Ran chkdsk (WITHOUT /f) and received a "file record segment ### is unreadable". The segment numbers weren't contiguous but after a half hour I stopped the chkdsk because I didn't want to make matters worse. I tried copying some stuff off the drive but only got about 8 gigs out of 3.63TB, I was using xxcopy (not xcopy) and after a while I just started getting copy failed messages and explorer.exe would hang and couldn't even be terminated with taskkill; the only solution was to power off. The drive is pretty much filled with only about 138GB free.
My questions are these:
1. In days of old, I would use Media Tools Pro to clone the hard drive in reverse, however since that is a DOS application, I'm pretty sure it will not see this 4TB (3.63TB formatted) drive correctly. So, are there any software only solutions that can clone in reverse drives > 2TB?
2. This external USB comes with a USB bridge that provides sector translation such that a 4TB hard drive could be seen in XP, so if you take the hard drive out of the USB enclosure and just connect it via SATA you don't see partitions/file systems even when the drive is healthy. I know this because I have a second external hard drive of this type (which is still good) which I disassembled and connected to a SATA port for contrast. So, if I were to try to clone this drive, should I do it in the USB enclosure or just straight to a SATA port?
3. The noise that I hear from the hard drive at certain times is a "loud" (relative to normal) reading noise, which I believe is the read head seeking the same piece of data/sector over and over again. It doesn't sound too different from the dB level of hard drives 20 years ago. Don't know if this noise is as instructive as I hope, but I'm wondering if I should leave the hard drive plugged in to keep it hot, or if I should unplug it and let it cool down. Prior to this it was connected to a computer almost all the time.
4. When I do copy data successfully off the hard drive, it only lasts for about 10-20 minutes (roughly) before it consistently gives me "copy failed" messages.
5. I took the USB bridge off the other external hard drive I have of this kind and swapped it to see if that was the problem, and unfortunately it wasn't. There was no appreciable difference using either one in how the drive behaved.

In general, I'm looking for a plan of attack or strategy on how to go about recovering the data on this HD, as it has most of my music (among other things), so I REALLY don't want to lose it. Thank you for reading.