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I am having an issue with USB drives and Windows. When any external media device is attached to the computer in Device Manager I receive the message unknown USB device.

This happens with USB drives and MicroSD/SD cards. I tested the USB drivers and they worked fine on another computer. I made sure I properly ejected it (safely remove device) too. My USB devices use to be recognized on my computer before.

Why is this happening and what can I do to correct it?

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Which Version of Windows? – Robotnik May 11 '12 at 3:11
up vote 7 down vote accepted

There are many people also having similar problems with Windows not recognizing USB devices. The issue is with .inf files.

  • Copy the entire C:\Windows\INF folder to C:\usb_fix or (whatever folder name you like to call it)
  • Go back into Device Manager. Select the "Unknown USB device"
  • Choose Update Driver
  • Select Choose Location
  • Enter the path of the new folder you have created earlier.
  • Windows will now search for the driver in this folder location instead of the previously selected one.
  • You should see your device being recognized – now you're able to open them in Explorer.
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Thanks Riley, It work. You are a lifesaver. – Master Pcman May 11 '12 at 3:36

Since you are saying that the problems occur to both SD and USB, the common denominator is your motherboard. You can always used windows to install/upgrade your motherboard's chipset drivers, but you should preferably look for your motherboard drivers online (If it is a notebook, just look for the model and you'll find the updated drivers). Even if it was working correctly, the drivers could have been corrupted somehow.

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