# USB external hard drive comes up as unknown device



## markhimself (Mar 20, 2007)

Hi there 
I have connected my USB external hard drive to my machine and i get an error message that the device is malfunctioning. I have installed SP2. And run Virus programs but to no avail! The Hard drive does work on other Machines so its deffinately not the hard drive. The External drive has also been set to slave. Please help!


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## geek73 (Mar 29, 2007)

Howdy markhimself.. Try setting the External to master.. When you open your device manager are there any yellow question marks besides the Hard drive?

Also right click ym computer..Click manage..Then disk management..Does the HD show in there/


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## markhimself (Mar 20, 2007)

howdy!!
Device shows up as unknown device under the universal serial bus heading.
If i set it to master wont it conflict with my other hard drives? Also it used to work as a slave device before and all of a sudden just stopped working! Wierd!
Ive tried deleting the vid entry in the registry aswell but that doesnt work either! hmmmm..


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## geek73 (Mar 29, 2007)

Do you still have the drivers for your motherboard? Maybe it got corrupt and now it is not shwing up


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## Andy128 (Nov 6, 2004)

Have you tried system restore to a point prior to it failing?
Also- is it the onboard usb port? Might want to install a usb-pci card and give that a try.

Andy


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## Lydokane (May 24, 2005)

Mark,

Changing the drive to master will not mess with your current hard drive config. Andy is on the right track with the USB reply. If you don't have access to a PCI card try using a different plug that is already available. You could also try a different cable.

Does the external drive have its own power supply or does it get its power from the USB port? If it is drawing power from the USB you might be underpowered. 

Also, just to troubleshoot, I would remove any other USB devices that aren't necessary (flash drives, cameras, scanners etc.).

Lydokane


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## markhimself (Mar 20, 2007)

Yes the external drive does have its own power supply, Also read on another forum that Unpluging the PC from the wall socket would solve it but that didnt work either, cant be the cable because it works on any other machine i plug it into. Its not the usb port itself either because i have shuffled it through all 8 ports that i have even including the one that the mouse was plugged into! Unfortunately cant use system restore because it has been disabled! Installed SP2 which should include the USB drivers, even downloaded USB drivers seperately and installed them but that didnt work either, running out of ideas!!!
This is so wierd!


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## Lydokane (May 24, 2005)

Was the external HDD on this computer originally or did it come from a different computer?

What is on the drive?

Lydokane


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## geek73 (Mar 29, 2007)

Can yuo open it up and make sure everything is still connected? Maybe somthing got popped loose.


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## markhimself (Mar 20, 2007)

Have opened the drive and made sure everything was connected,The drive works if i plug it into any other machine! The drive was bought only to be used in the external casing and contains only movie files.
Must be something i can do


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## nickster_uk (Feb 7, 2005)

I've recently had this problem when both my front panel USB and card reader were connected to the board. If both were connected, only the media reader would work properly and I got 'unknown device' from the USB ports. However, unplugging the media reader from the board resulted in the USB ports working as normal. All used to work fine so i'm currently investigating with new USB cables to see if that helps.


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## seriously (May 14, 2007)

no no no no no guys........

i have a computer with this problem. if you have searched the internet enough you would have found that the problem is with the motherboard chipset. let me guess, your motherboard is not using the intel chipset, most likely a VIA chipset (which mine is). i don't know if other non-intel chipset motherboards have this problem though.

a post for help at gigabyte website (my motherboard) received the familiar "we have not heard of such problem before" type of reply. went to VIA website and the answer was "most likely your motherbaord wasn't certified for win XP". wait a minute, it clearly writen on the box that it support the latest win XP!?

cutting the story short, the best i've got now is the external hard drive working intermittently. i won't even try to copy data to it because it could fail with error at any time.

the final solution? make sure you buy computer with intel chipset in future. although i believe newer motherboard with VIA chipset might have worked, you never know when they'll release new devices that only work with the industry standard intel chipset and not others. then you ended up same situation again.

by the way, adding anothe pci usb card (even one with the NEC chipset) did not work. also, usb external hard drive is not the only device that doesn't work with my motherboard. some older usb canon scanner and video camera won't work too.

i've already given up awhile ago.......

seriously


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## markhimself (Mar 20, 2007)

Hey man thanks for the reply 
it was always a riddle burning in the back of my mind for so long, I also gave up the fight as i couldnt find answers anywhere but thanks to you i now understand!

Seriously Thanks!!


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## sling34 (Dec 7, 2009)

Ok, so I know this is after you gave up... and a long time after you posted this...

I found a quirky solution to this Unknown Device problem. It does have something to do with faulty USB controllers or Root Hub, somehow even manually trying INF updates for said device comes up fruitless.

The solution to getting your hard drive reading again? Granted, this is only if the drive itself isn't corrupt...

1) Plug in a USB hub into an existing USB port.
2) Plug USB cable for hard drive into USB hub.

I did everything else on the internet suggested, short of throwing the drive and enclosure out the window. XP would give me an balloon popup error saying "The device has errored or has become corrupt - please troubleshoot or replace device" or something to that extent.

On a whim, I grabbed a 4 port USB hub i have for another computer, plugged it in via the USB to mini-USB cable, then plugged the USB cable from the hard drive into said HUB... and VOILA!! it started recognizing it again in My Computer/Explorer.

Hope this helps, for anyone else who gave up. Sorry to bump an old post, but it's frustrating and hope this alleviates hours of hair pulling and cursing.


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## seriously (May 14, 2007)

thanks, sling34, for the suggestion. believe it or not i still have that computer 

i'll like to buy one and try it out just for the curiousity sake but like to know if you used a powered or non-powered usb hub, or it doesn't matter?


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## kerflot (Mar 28, 2009)

seriously said:


> thanks, sling34, for the suggestion. believe it or not i still have that computer
> 
> i'll like to buy one and try it out just for the curiousity sake but like to know if you used a powered or non-powered usb hub, or it doesn't matter?


Use a powered hub to be on the safe side.
Perhaps find a brand that sells models with and without power units so in future if you need a second hub that's unpowered you can get the same model. So if one hub breaks done you can use the other for those urgent jobs.


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## djrobsd (Jun 19, 2005)

I tried everything, updating drivers, inf files, removing, reinstalling, power cord unplug trick, etc... I *ALMOST* gave up, but the ONLY thing that worked for me was a powered USB hub. Some people have even said this doesn't work. It makes no sense to me, but my motherboard is about 2 years old, so who knows, maybe over time the USB power just starts to die!

The one that worked for me was a Belkin F5U234v1

Hope it sticks!

By the way, had the SAME problem on my 24 inch iMac.... But it was easy to fix, I plugged directly into the USB port instead of the port on the side of the keyboard.


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