Card not detecting external hard drive.

I have recently bought your USB 3.0 I/O Card, and I am experiencing problems with my external usb 3.0 hard drive not being detected by my computer. I have updated all the drivers for the card but still no luck. My card is working for my wireless router card though. My external is powered through usb. Can you tell me how to fix? It was working for a while then just randomly stopped working one day.

Hi Daniel,

Thanks for posting here! I’m sorry to know about the trouble you are having connecting the USB 3.0 external hard drive through our Plugable PCI Express to SuperSpeed USB 3.0 Two-Port Expansion Card.

Some quick questions to help understand the setup and the issue better-:

  1. What is the make and model of the USB 3.0 External Hard Drive?

  2. What is the current version of the OS installed on the system?

  3. What is the version of drivers and firmware installed on the system for the card?

  4. If the External Hard drive is connected through a USB 2.0 port on the system, is being detected?

Once you post back with this information we will figure out the next steps.

Thanks for your patience!


  1. I have a Western Digital My Passport Essential SE 1 TB USB 3.0/2.0 Ultra Portable External Hard Drive

  2. Windows 7

  3. Driver Version:

  4. Yes the hard drive works on usb 2.0 fully functional no problems

While connected to usb 3.0 card it will turn on, disc is spinning but not recognized by computer.


Thanks for the information! Do you have access to any other system that has a USB 3.0 port? If yes, could you connect the WD External Hard Drive through USB 3.0 on that system and check if you do see the issue on that system or not?


I do not have any other usb 3.0 ports to test my drive on unfortunately. I am starting to believe that there is a problem with the 4 pin adapter on the card. My hard drive is running while plugged in, that is the disk is spinning, but it cannot read any data off of my hard drive. When I went to look at the card itself, the connector was not very stable, and seems that there may be a fault in it.

Is this a common problem related to my card?

I wanted to jump in with a little background:

The 4-pin (Molex) power connector on the card is to get the card from ~1.2 Amps that the card can convert from the available 12V power on the PCI bus up to the full 1.8 Amps that two USB 3.0 devices could consume (USB 3.0 raised the per-device power limit from 500mA per device with USB 2.0, to 900mA per device).

That said, all of that is theoretical so far – there are actually few USB 3.0 devices that use 900mA. And if you’re running just a single device (as you are), then the card has plenty of power without the molex connection – the 4-pin power connection actually isn’t needed.

USB 3.0 is still maturing, so when something isn’t working, we have to look at every component in the chain. But to rule in or out our card, we’d like to get you a 2nd pre-tested unit to compare against. That will help figure out whether it’s something on the drive side or the host controller side.

If you send a quick email to us at with your Amazon order number and a link to this thread, we’ll take care of you.

Thanks for your patience!