My external hard drives "disappear" and are not recognized by Windows 7 after it's been running for 5 to 30 minutes.

I installed Windows 7 on November 1 to the computer which had been running Vista since its purchase in July.  I have two external hard drives... a 250 GB Seagate FreeAgent (it has its own power source... hooked up via USB) and 1 TB HP Personal Media Drive (slides into the Personal Media Drive bay of my HP computer).  I have had the Seagate drive for two years, and it worked well with my old computer... never a problem.  I have had the HP drive for two months, and it has experienced only light use.


Last week, after Windows 7 had been installed for a week with no issues, when I went to save a .doc file on my Seagate drive, it said that the drive could not be located.  I ended up saving the file to internal disc and restarting the computer.  After the restart, my computer recognized my Seagate drive, and I was able to save the file.  A day later, I attempted to save an image I had been editing, and the same thing happened.  The problem began to occur more frequently.  Then, last night, I opened iTunes and tried to create AAC versions of songs from 2 new audio CDs.  Halfway through then ten songs on the first CD, an error message popped up indicating that the Seagate drive was no longer there.  After another failed attempt to import the songs, I popped in the other CD, but iTunes could not copy the files to my desired directory.  I changed the directory where I save files to the C: (internal) drive, and songs were successfully copied.  I restarted my computer and tried to import songs on the Seagate drive once more.  It finished the songs on the first disc successfully, without incident.  Then I put the second disc into the CD drive.  After importing one song, an error message again popped up.  I clicked the Computer icon on the desktop, and it indicated that the Seagate drive was still there.  I double-clicked the Seagate drive, and instead of displaying files and folders, all it said was "This folder is empty."  I then disconnected the Seagate drive from my computer.  The Computer folder still displayed the Seagate drive as connected to the computer.


Fearing Seagate drive failure, I pulled out my old computer and hooked up the Seagate drive, just to check.  All files & folders on the Seagate drive were present.  I decided to hook up my HP Personal media drive to my old computer and proceeded to copy all files on the Seagate drive to the HP drive.  This took about two and a half hours.  I then hooked my HP drive back up to my new computer and tried saving Word files, image files, and importing audio files from CD into iTunes.  Again, just like the Seagate drive,   things worked well to start, but after 5 or 10 minutes, the drive had disappeared.  Every time I restart my new computer, the drive is there for anywhere from two minutes to half an hour, and every time the drive disappears.


I have tried going in to Disk Management and rescanning disks.

I have tried going in to device manager and uninstalling both Seagate and HP disks, then restarting the computer, and then hooking them up once more.


I have no idea why the drive would be recognized for a short amount of time and then disappear.  I have checked for loose cables.  It's just bizarre because I didn't really notice any issues with either drive for the first several days after I had installed Windows 7.


I appreciate any assistance!


Question Info

Last updated August 14, 2018 Views 14,702 Applies to:
How I solved my problem:
- changed the USB cable by a grounded one.
- used SyncToy to do the transfer instead of Explorer

The new USB cable (I took the printer one) gave a better transfert rate and more stability when used with Windows Explorer. But still have drive disparition.
SyncToy, you can get at the link below, is slower than Explorer but more reliable and it's interesting for resuming copy after a problem. I think it doesn't use all the USB bandwith and this solve the problem.


ps: sorry, my question is not the answer, this one is.

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