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I have a strange situation here. I got a new Toshiba P850/04P laptop, there are 4 USB 3.0 ports, 2 on the right and 2 on the left.
When I plug my WD 1TB Passport Essential into the 2 ports on the left, the drive keeps disconnecting and then connecting again, on and off. Sometimes it works well for 1 hour and then disconnects and even shows the "please format your drive" message.

What is odd is:

  1. this WD 1TB Passport Essential works perfectly on those 2 ports on the right side.
  2. It has been working fine on all other PCs and laptops.
  3. Another 500 GB WD passport can work with the USB ports on the left (the ones 1TB can not), also all other devices can work with all 4 ports.

I am really confused! Does anyone know what the problem could be?

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up vote 1 down vote accepted

It's possible another device connected to that USB root hub is drawing enough power that the 1 TB drive is insufficiently powered. You can see what other devices are on the same USB Root Hub by doing the following:

  1. Click the Windows (Start) menu, right-click on Computer, and select Manage
  2. Click on Device Manager
  3. Click the View menu and select Devices by connection
  4. Expand ACPI x64-based PC/Microsoft ACPI-Compliant System/PCI bus, then expand each USB Enhanced Host Controller as far as it will go. You'll be able to see all the devices that are connected to the controller and could be drawing power from it.

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First, unplug all other USB devices from your laptop. If that doesn't solve the problem, it might be the case that some built-in device (such as a webcam) is drawing power. You can try plugging the drive into a powered USB hub, then plugging the hub into the USB port on the left side of your laptop to confirm this.

If you don't have a powered USB hub to perform this test, try to observe if there is anything that could be triggering the USB hard drive to disconnect--for example, when you use the webcam or rip/burn a CD/DVD.

Try downloading and installing any driver updates from Toshiba.

If the problem still occurs under "normal" use with only the 1 TB drive plugged into a USB port on the left and the latest drivers installed, I would contact Toshiba support because it's possible the laptop is defective.

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Thank you very much for your detailed advice! I checked Device Manager, no other things are sharing this port with this 1TB WD drive and I do not have anything else plugged in any other USB ports. The problem is till there. Also, what I can not understand is another 500 GB WD My passport drive works perfectly in this port, is it possible 1TB drive will need more power than a 500GB drive? In Device Manager, this laptop shows 500mA power per port – user143863 Jul 4 '12 at 17:11
AFAIK, USB 3.0 is supposed to supply 900mA. Some drives do draw more power than others, but I would expect a bus-powered drive from one of the major manufacturers to run fine on 500mA. It's possible the drive or laptop is defective, and since the drive works fine on some of the laptop's ports, I'd be more inclined to suspect the laptop. – rob Jul 5 '12 at 0:12
Hi Rob, Thank you very much!!! I got a externally powered USB 3.0 hub, this WD drive is working fine now. So I guess the power supply of these 2 ports are not so properly designed, which may be a problem of many Toshiba matchines. – user143863 Jul 5 '12 at 15:05
Now, while I can use this WD drive, this powered USB hub sometimes (not often) drops out and Windows 7 keeps giving the warning sound, at the same time, I can still use this WD drive with no troubles, even that happens when I was transferring files, it does not get interrupted (very funny). I guess there is some connection problem with the Hub. – user143863 Jul 5 '12 at 15:12
Glad to hear adding a powered hub helped, but the new problem is still a little disconcerting. Maybe the contacts in the connectors are dirty. You could try cleaning them with a small Q-tip to see if that helps. I'd still contact Toshiba in case the laptop is defective. If you bought it at a local store, you could take your portable hard drive to the store to see if it works on a display model. If it turns out you just need to exchange your laptop, image the laptop's hard drive using Acronis TrueImage or one of the free tools at, exchange laptops, and restore the image. – rob Jul 5 '12 at 18:25

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