CHKDSK for multiple drives reports "An unspecified error occurred..."

CHKDSK, run either by scheduled during restart, or in Safe Mode Command Line, or from a separate USB boot disk, all show the exact same allegedly "fixed" errors over and over again. They never actually get fixed!

Also, on 4 out of 7 different disk drives -- including two Samsung SSDs which "SSD Life Pro" says are in excellent condition and will last at least 8 more years -- keep reporting an error I've never seen before:

Code:

An unspecified error occurred (766f6c756d652e63 461).

Fortunately, the 64-bit Windows 7 Pro boot disk never shows an error, but I get these repeated and allegedly "fixed" CHKDSK errors, for example, when I'm trying to clone my system partition to any of a few different disk drives and before the cloning can complete I get one or more CHKDSK errors - even though there are no CHKDSK errors from the source disk/partition!

I've checked and re-checked for rootkits and other malware using MBAM and Avira Pro, and no problems are ever reported. I've exhaustively checked the RAM using MemTest86 v7.01 for 20 passes each over two days, and again, no problems are reported.

These inexplicable errors are driving me nuts! And it's seems extremely unlikely that these are any sort of common problems, so I need some creative thinking, please. I thought maybe a PSU problem, but it's a 2-3 year old Corsair 850 and I'm not using anywhere near 850 watts. Also, the mobo and disk temps are typical and even on the low side a bit. I don't believe there's anything wrong with the disks themselves, but how likely is it that some chip on the ASUS Z97-A mobo -- say, a SATA chip -- is flawed? If it's likely, how can I test this?

I'm desperate here, folks! Please help!

Hey, that's nice thinking, Ranger4! Thanks!!