How to get access to the USB hard drive which is not recognized by the PC

The USB hard drive consists of the three principal parts

  • a hard drive, either regular 3.5" (desktop) or 2.5" (notebook)
  • the USB box (enclosure) housing the hard drive and a controller converting USB (or FireWire) signals to IDE or SATA.
  • the optional power supply unit. The PSU may be either a separate part or integrated into the USB hard drive box. Most of the 2.5" enclosures get power from USB bus and are not equipped with a separate power supply.

First simple steps

If there is a clicking, grinding noise, high pitched whine, or an otherwise unusual sound from the drive, it may be mechanically damaged.

Try the following:

  1. Reseat the power cable at all connection points (plug to outlet, power cord to power supply, power supply to the box).
  2. Try a different USB cable
  3. Try a different USB port

Getting the hard drive out of the USB box

If the above did not help, you need to disassemble the USB box and get the hard drive out of it. Then, either connect the drive directly to the motherboard, or try a different USB enclosure.

The exact specifics of disassembling vary from model to model, but usually a simple screwdriver is enough. A few notes:

  • The enclosures that are sold as a single unit and not supposed to be taken apart, like WD Passport, tend to be little more difficult to disassemble. Also be aware that disassembling such a unit may void its warranty.
  • Consider searching YouTube for, e.g. "disassemble WD Passport". There is a good chance to find a video tutorial for your particular model of the USB box.

Connecting a hard drive to the motherboard of a desktop PC is pretty straightforward if ports on the drive and the motherboard are compatible. If they are not, either find a compatible one or try another known-good USB enclosure.

  • SATA drives can be connected to SATA ports without any limitations.
  • IDE (Parallel ATA) drives cannot be connected to SATA ports and vice-versa unless you have a special converter.
  • IDE drives can be connected to IDE ports, but you need to set Master/Slave jumpers properly. Also, connecting a 2.5" (notebook) IDE hard drive to a 3.5" (desktop) IDE port requires the appropriate converter.

If it was the problem the box rather than with the hard drive itself, the data would be readily accessible once the hard drive is successfully connected.

If the drive is recognized but the data still inaccessible, refer to how to unformat a hard drive for further guidance.

Otherwise if the hard drive is still not recognized by PC, it is most likely mechanically damaged beyond DIY repair. Consider using a data recovery service to get data from the drive (how do I find a data recovery service?).

Reference information

How to tell if the hard drive is recognized by the PC?

How do I tell IDE (PATA) from SATA drive?

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