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Windows 7: external HD not recognized

01 Aug 2010   #1

windows 7 home premium 32 bit
external HD not recognized

whenever I plug in my Buffalo USB external hard drive, I get nothing. It shows up in device manager but not in My Computer. The light on the hard drive comes on \Windows just won't recognize it. Any ideas? there are no yellow flags in device manager its only 6 mths old. it worked at start and gradually just started not finishing the backup. now it doesn't work at all

My System SpecsSystem Spec
01 Aug 2010   #2
Mellon Head

Win 7 Pro x64/Win 10 Pro x64 dual boot

It sounds like it might be broken. Have you tried plugging it into another USB port? Or into another computer? Some of these little USB hard drives can overheat and fail pretty easily. I haven't heard of Buffalo drives before so I don't know anything about their failure rate, but to me, it sounds like the drive itself is beginning to fail, if it hasn't failed completely already.
My System SpecsSystem Spec
01 Aug 2010   #3

Windows 7 Home Premium x86-64

Right click Computer, select Disk Management, check if its recognized. If it is, get an Ubuntu live cd and back everything up to another source, then reformat the drive back in Windows.
My System SpecsSystem Spec

01 Aug 2010   #4

Windows 7 Professional SP1 64-bit

Can you see it in disk management when it fails to appear in My Computer?
My System SpecsSystem Spec
02 Aug 2010   #5

windows 7 home premium 32 bit

thanks everybody for the reply i got it working . i changed the drive letter in disk management . how to git there, click control panel , administrative tools , computer management, then click disk management .
My System SpecsSystem Spec
02 Aug 2010   #6

Windows 7 Professional SP1 64-bit

Glad to hear you got it working.
My System SpecsSystem Spec
23 Nov 2012   #7
alexei F

Windows 7
Buffalo HD-PET640U2/R-EU external HDD not recognised

Buffalo HD-PET640U2/R-EU

Hello. I've been having similar problems with the above drive, and found this thread which seemed helpful. I've had the drive for about a year & a half. It worked fine (on Win XP Home) up until a few days ago, when I connected it to my new laptop (Win 7).

On connecting, a warning message came up saying that Windows had detected disk errors - did I want to scan it? I said Yes, it completed the scan (no errors), but I couldn't access any of the files in Windows Explorer. I Safely Removed USB Hardware and tried again, but said No to the error scan ("Are you sure, some files may be corrupted?"). On continuing, I could see all my files.

I then selected Windows Scandisk, and once the scan completed the HDD was very slow to select. It didn't show any of my files again, and showed the following error messages whenever I tried to access it:

Local Disk (E)
You need to format the disk in drive E: before you can use it.
Do you want to format it?

Error checking
The disk check could not be performed because the disk is not formatted.
The disk check could not be performed because Windows can't access the disk.
Would you like to format the disk?

Location is not available
E:\\ is not accessible.
The volume does not contain a recognised file system.
Please make sure that all required file system drivers are loaded and that the volume is not corrupted.

I have tried it on all 4 USB2 & USB3 ports, and my other Buffalo external HDDs work fine.

The HDD appears as 'Buffalo HD-PETU2 USB Device' in:

Control Panel\\Hardware and Sound\\Devices and Printers

Control Panel\\Hardware and Sound -> Device Manager

and in

Control Panel\\System and Security\\Administrative Tools -> Computer Management -> Disk Management

as '596.17GB RAW Online & Healthy'. My other HDDs appear as 'NTFS' or 'FAT32', not 'RAW', and I think (but am not 100% certain) that I'd formatted the problem disk to FAT32 when I bought it.

In My Computer the disk only registers as 'Local Disk (E)'.

I have tried to update Drivers but Windows says I already have the most up-to-date ones for the HDD.

I also tried reassigning the Drive Letter to (K), but no change.

This disk was the backup for my most important files when I changed to my new laptop, and so I really don't want to lose them. I've read on some sites that I can still attempt to recover the files even if I format the drive (as long as I haven't written anything new to it), but I don't want to risk that unless there's no alternative. Equally I'd rather not try opening the drive casing up - on one forum it was suggested that the 'power supply component' for the HDD might be the problem, and opening the casing, removing the p/supply comp and running the drive in another hard drive enclosure might work.

I contacted Buffalo and they just suggested formatting it then trying to recover the files.

Does anyone have a better idea?


My System SpecsSystem Spec
23 Nov 2012   #8


Please start a new post.
Post starter, please mark this post as SOLVED.
My System SpecsSystem Spec
23 Nov 2012   #9

Windows 7 Home Premium 32 bit

Hi Alexei F,

Welcome onboard.

I have seen your post in the PC Advisor forum too.:)

And you have been advised to use TestDisk.:) ( but it is not me who advised. )

Well, I shall go in a graded manner on this issue.

1. Connect your external hard disk back into an Windows XP machine and check whether you can access the files. If you can, then copy all the files into another media - say another ext. HDD. (Check all your files are OK and not corrupted. Unfortunately you had run scan/check disc in adverse conditions which could possibly corrupt the files.) If everything went Ok, format your ext.HDD in Windows 7.

2. Boot from a live Linux CD/pendrive and if that could access the files, copy them to another HDD either to your internal drive if it has suficient space or to an external drive.


Lucid Puppy way to recover files from a non-bootable computer

whichever you may prefer.

3. Use TestDisk. Follow this guide in using.

How To Fix: External Disk Drive Suddenly Became RAW

Note: You need not create a PartedMagic CD or pendrive. If your Windows is stable, install TestDisk - Windows version and follow the instructions on using TestDisk only.

You may also refer to the guide here to familiarise yourself with TestDisk.

Regain a lost drive using Test Disk - An Illustrated Guide

Note: Post #23 therein also lets you know how to create a bootable DOS pendrive and run TestDisk with it, if you prefer to take Windows out of the loop.

Let us know how you are progressing.
My System SpecsSystem Spec

 external HD not recognized

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