All files from unbootable HDD not visible through Explorer

Is there some (unknown to me) Explorer limit on file display? One of my Windows 7 PCs decided to not boot anymore, or if it would boot, the response was glacially slow. Repair couldn't fix it, my restore points had disappeared, so I took out the HDD and hooked it up to another W7 desktop. One folder on that (damaged) HDD has a ton of music, which I stupidly never backed up. I attached an external drive to the working computer, intending to backup those files from the non-booting HDD before a reformat and reinstall.

When I open that drive (J:) through Explorer on the working desktop, I see a long alphabetized list of folders and files - but nothing after the letter 'R'. I copied all of the files that were visible to an external drive, but for the rest of the files I had to go into DOS. There I could see the files that started with 'S' and 'T', etc. I could use DOS to copy them to that same external drive, but I wondered why it was necessary.

Is the some file count or folder size limit on what Explorer can display? According to DOS and Explorer, not a single file is missing from A-R on Explorer. Just nothing after that.

Ztruker said:

Run chkdsk /r against the USB attached hard drive, see if it finds and corrects an file system corruption. Once it's done, see if you can access everything.

While the drive was still in the computer (and bootable), I initiated a chkdsk /r before I went to bed the other night. Eight hours later it was still on step 1 of 5, was only 4% through that step and was displaying tons of errors. An hour later it still hadn't budged from that 4%, so I shut it down and removed the drive.

I certainly can run chkdsk from the command prompt on the computer to which the drive is currently slaved, but I was nervous about running it before I'd gotten all I could from that drive, thinking that maybe chkdsk might wipe out some of my files.

AddRAM said:

There`s nothing that should stop explorer from seeing everything, never heard of it.

Then it's my dubious pleasure to introduce you to something with which you're unfamiliar. Perhaps it's some bizarre symptom of corrupt files - about a half dozen files on my J: drive were corrupt and could not be copied to an external drive. All the files that I did copy (close to 1000), through both Explorer and DOS seem complete and undamaged, so it's really more of a curiosity than a problem.

Now than everything's been copied, I'll run chkdsk and see if it changes anything.

Ztruker said:

Sounds like the hard drive has gone bad.

Check the hard drive with the manufacturer's diagnostic tools.

7 Free Hard Drive Testing Programs
Hard Drive Diagnostics Tools and Utilities (Storage) - TACKtech Corp.
Bootable Hard Drive Diagnostics

Oh, I'm in complete agreement - I just wanted to get the good stuff off the old drive so I could transfer it to a new drive. I am running chkdsk on that now slaved drive. I don't anticipate a happy ending.