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Old Jan 5, 2007, 5:27 PM   #1
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I have an external USB HDD problem on my computer. Imnot really sure as to what happened really. I have 2 external HDD and they were working fine until I got the 3rd one. I unplugged all of my computer to organize everything and when I plugedit in with the new USB HDD it wasnt detecting any of my external drives. Its detecting my USB Key and my Zen player and digital camera usbcard. I have tried to trouble shoot it every way I could. The external HDD works fine on my laptop and I know its not the USB port or the cable. All that the system says is that Unknown Device. I have installed all of the needed drivers.I have looked over Microsoft websitefor help but nothing that they have there works for my computer. I have all up to date patches and service packs yet nothing makes my computer detect my external HDD. What can you suggest?
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Old Jan 5, 2007, 7:23 PM   #2
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It might be a power problem. Do your external HDD's have their own power cords or do they rely on the USB port for all their power? If they rely on the computer for their power, maybe your power supply just can't handle the extra load. Same if you are using a USB hub, you might need a powered hub.

Have you tried connecting the new drive and one of the old ones to see if it works? If it does work as one of two drives rather than as one of three drives, that could eliminate some possible causes. Is there a BIOS limitation on how many HDD's you can have hooked up at once? If so, maybe something like a RAID 1 adapter might be neccesary. You might get better answers from your motherboard manufacturer than from M$.

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Old Jan 8, 2007, 8:07 AM   #3
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It seems that your new external HD has been formatted properly because it is recognized by your laptop. When your PC says "Unknown device", its USB seems to detect a new device but cannot identify it - this is rather unusual because Windows usually have all the drivers of most hard drives. In fact, I have never installed anything when I bought my new external USB HD.

Do you connect your new external HD (or any other drives and devices) through a USB hub? I find that, sometimes when you connect a new device through a USB hub for the first time, it is not recognized by Windows (either as an "Unknown device", or not detected at all). The solution to this is to plug the new device directly into the PC's built-in USB port, just for the first time - you can then plug it into the USB hub and it will be detected and identified by Windows the next time you switch it on. If this is the cause of the problem, plugging the new HD into the PC's USB hub will allow recognition of the device, without the need to eg. re-install the driver. You can then plug it back into the hub for further use.

If everything else fail, you may try to re-install the driver of the new hard drive:

"Control Panel" -> "System" -> "Device Manager" -> it should list an "Unknown device" (if not, look into "Disk drives") -> double-click -> "Drivers" tab -> "Uninstall"

Then unplug the USB of your new external HD

If you have installed anything from the CD that came with the external HD, go to "Start" menu and see if you can uninstall those (if not, try from "Add/remove program" in "Control panel").

You can then either try re-installing the included CD before plugging in the new HD, or just plug the device ( remember into the PC's USB port, not in the USB hub) and switch it on, and see if your PC recognizes it and install any driver for it.
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Old Jan 9, 2007, 2:34 AM   #4
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I read something interesting a few days ago. A tech support guy said that if you don't use the "Safely Remove This Device From Your Computer" doohicky in your system tray when you disengage removable drives, that eventually, the computer will stop recognizing USB devices.

Now, I don't have an external drive(must correct that, sometime), so I don't know whether simply turning off an external HDD -- without disconnecting it from the computer -- is cause enough to have to use the "Safely Remove" etc., feature or whether that just comes into play when actually disconnecting the USB cable.....

If this doesn't apply to you, then this has still been and interesting bit of trivia.

Grant
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Old Oct 7, 2007, 7:34 PM   #5
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Hello there, I have a same problem. It is always showed Unknown Device. I have been tried everything I can, but external USB HDD still now work. Have you resolved the issue? Could you please give me some suggestion?

Thank you!
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Old Oct 7, 2007, 9:03 PM   #6
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Your computer should automatically recognize a hard disk drive. If it only shows up as 'Unknown Device', then there could be several things that could be wrong.

First, make sure the power supply for the external HDD is working properly. When the external HDD is not connected to the computer, do any of the leds light up? If none of the leds light up, the power supply or cable may be bad.

Second, make sure the hard disk is spinning. Again, when the external HDD is not connected to the computer, when you turn it on, do you hear or can you feel the disk spinning up? If the disk doesn't spin up, a cable inside the case may have loosened, and the HDD may not be getting power the drive may have failed.

Third, try a different USB Cable.

These are some of the simple things you can check for. Hopefully, checking these things will help you discover the problem.
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Old Oct 7, 2007, 9:07 PM   #7
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granthagen wrote:
Quote:
I read something interesting a few days ago. A tech support guy said that if you don't use the "Safely Remove This Device From Your Computer" doohicky in your system tray when you disengage removable drives, that eventually, the computer will stop recognizing USB devices.
This may or may not be true, depending on how the properties of the device are set. If you right-click and select properties, there will be menu selections to allow or disable write caching on the drive. Disabling write caching allows the device to be removed without problems, or using the 'Safely Remove Device'. I use this option for my camera memory cards in the card reader. (WinXP).

What I would try, with the case of Unknown Device, would be to open Disk manager under Admin Tools/Computer Management. If disk manager see the device with a drive letter, right-click on the drive, and select 'Mount drive'. This should allow Windows to recognize it.

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Old Oct 7, 2007, 9:19 PM   #8
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VTphotog wrote:
Quote:
granthagen wrote:
Quote:
I read something interesting a few days ago. A tech support guy said that if you don't use the "Safely Remove This Device From Your Computer" doohicky in your system tray when you disengage removable drives, that eventually, the computer will stop recognizing USB devices.
It may stop recognizing USB devices, but only during the remainder of that session. Restarting the computer will reset the OS and the USB controller(s).

VTphotog wrote:
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...or using the 'Safely Remove Device'. I use this option for my camera memory cards in the card reader.
Actually, you can right-click on the drive icon for a memory card, and from the context menu, you can select 'Eject'. Then you can remove the card from the reader. When you use 'Safely Remove Device' you might tell Windows that you don't want to use the card reader anymore (during the current session.) Then Windows won't recognize another card that you mightinsert later on during the same session.
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Old Oct 9, 2007, 12:02 AM   #9
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VTphotog wrote:
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Disabling write caching allows the device to be removed without problems, or using the 'Safely Remove Device'.
Perhaps I should have written " --or WITHOUT using 'Safely Remove Device'."

I just plug and play, without using any of the taskbar menu items. I do put card in reader first, then plug in reader, and reverse when removing, if it makes any difference. Haven't had a problem yet.

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Old Oct 14, 2007, 5:15 PM   #10
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This is a symptom that I have had happen on a number of occassionsin the past.

Shutting down and restarting sometimes isn't sufficient to properly reset the USB ports. I have found the following to be the only method that enables connecting certain USB drives (this also happens to work on occassion when an IDE internal drive isn't detected properly)

Ensure power supply unit for external drive is connected and switched on. Connect the external drive to USB socket as standard.

If not recognised perform shutdown sequence. Once computer is shut down properly, PHYSICALLY UNPLUG THE POWER SUPPLY UNIT LEAD FROM THE BACK OF THE COMPUTER...(not the one connected to your hard drive)

Wait approx. 15 - 20 secs and replace.

Restart computer as normal.

You may just be lucky enough to find the drive now appears as standard within My Computer.

Fingers crossed... (this was certainly one of the stranger USB issues I've had, if anyone can explain why it happens I'd be quite grateful)

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