Event ID 51 Disk and 14 VolSnap

Excellent advice.

You might also be interested to know there's quite a discussion going on in another thread about spurious error 51s (without the volume shadow copy errors). https://www.experts-exchange.com/questions/25762694/Consistently-getting-paging-operation-errors-on-ext-drives-multiple-new-drives-Any-help-on-why.html?cid=1573&anchorAnswerId=30697052#a30697052

Seems something as simple as inserting blank media can throw the driver for a "loop" and raise the error that can be ignored? wtf? How stupid is that eh, "oops, ignore that error" ?
QUOTING
acl-puzz first posted http://support.microsoft.com/kb/244780   and
Jsmply and noxcho commented:
I found this post on the Seagate forum: http://forums.seagate.com/t5/FreeAgent-Products/Sleep-mode-and-Event-ID-51/m-p/32127
found these quotes interesting:
"ok, i have this answer from Seagate tech support: It seems that the Event ID 51 error is a generic event code that doesn't indicate anything harmful, but just that a drive has been connected."
"An operation that results in an event 51 warning is always retried.  An isolated event 51 warning is harmless if not accompanied by an actual error event, because obviously if the event is isolated in time, the retry was successful."
Also found this, although it still says it's an issue, just not one with the external drive.  Hmm . . .http://seagate.custkb.com/seagate/crm/selfservice/search.jsp?DocId=180615
UNQUOTE

Despite the possible spurious causes and "official responses" that say it can be ignored under those circumstances, it seems POSSIBLE in your case that either 1) the firmware and/or driver is buggy and needs to be updated or 2) there may be actual bad sectors being encountered on the drive so run drive tests.  Drive tests are manufacturer specific.

SpinRite 6 can help deal with bad sectors (it won't do manufacturer specific firmware tests or such), and you can read all about SpinRite on GRC website.  Most BIOSes do a lowsy job of reporting SMART details, but a free tool or two can be found (SpinRite for instance will show the SMART details)

Thanks for quick responses.  

I tried to use Sea Tools for Windows, but most of the tests where “unavailable”.  So I used Sea Tools for DOS.   I ran the Short DST and no errors were reported.  I then updated Intel chipset drivers.  Still had the same log errors and still couldn’t run a successful windows backup.   So I went ahead and ran the Long DST and 51 “serious” errors were reported.  For whatever reason, the computer restarted before I could save the test log, so I don’t have specifics as to the errors.  I also ran the Long DST on the other drive and it came up fine.   I’m guessing a new drive is in order.

Tarik, possibly, but I would still run memtest 86+ in DOS to make sure that your RAM isn't the culprit...as faulty RAM can cause of of the issues that you have encountered...and it'd be a shame to replace a good HDD!

Download found here:
http://www.memtest.org/#downiso

I just bought two new drives :/   I will run Memtest tonight and see what shakes out.  Also, this is a new system build of which the hard drives are the only component carried over from the old system.  Not that new components never fail, but worth mentioning.

Thanks for the follow up.  

Ran the Memtest last night and no errors were detected.  So I installed two new drives and thus far all is good.  Windows backup ran without issue and no errors have been reported so far.  I did however notice quite a difference in hard drive noise or lack thereof.  Anyways, thanks for all the guidance.

Great Tarik!  I forgot to ask if your drive(s) were making noise.  Often a "ticking" noise can be detected on a failing drive.  Glad to hear we could help.  Cheers :)