Files seen in folder, but progs say "File not found"??

I've just recently encountered a baffling problem: I browse to some folders in Explorer, and the files I expect to see are all there. However, every app I've tried to open or otherwise load these files reports "File not found"!

Opening a cmd window and performing a Dir command also shows all the files.

I found a couple of apps that promise to reveal extended info about specified files, but when I navigate to these files and select one to process, both of these tools also report "File not found".

I've run chkdsk and other utils on the drive holding these files several times, and each time it reports no errors found.

I'm running 64-bit Windows 7 Pro SP1 with the latest updates.

WTF? Can anyone help me resolve this weird issue, please?

What happens if you move the files to another folder?

I have finally figured out the problem, and it surprised me!

Here's the explanation... The disk drive that held the files in question was connected via an external SATA drive cage. Apparently, the slot in that cage that held the drive had a quasi-stable connection, either to the disk or the computer. I see no alternative than to conclude that it was properly connected when I browsed the folder (and ran the Dir cmd), and that the directory info was then stored in the disk cache.

But when I tried to open those files with various applications, the drive must have been disconnected at the time and -- as the files were obviously not present in the cache -- the opens all failed because the disk was disconnected at that time.

I confirmed that the disk itself was fine by connecting it using a different external cage and found that all the files were fine.

The main thing that surprised me was that Windows gave no apparent indication that the drive kept connecting and disconnecting over and over! Weird!