6 Ways to External Hard Drive Unknown USB Device

If you have problems fixing external hard drive unknown USB device, please continue to read this article, get the possible reasons and corresponding methods.


By Ivy / Updated on April 2, 2024

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The Problem: External Hard Drive Unknown USB Device

“I have a Western Digital external hard drive of 1 TB  I installed a 2.0 PCI card when I couldn’t get the device to work. This solved nothing. When I attach the hard drive it brings up a message that says the device is Unknown. I don’t know how to manually fix the problem.
I contacted western digital, but being plug and play they do not provide drivers for their products and have referred me to your website.Please help, it’s nothing more than an expensive paperweight at this point.”

External Hard Drive Unknown Device

Why Do You Encounter External Hard Drive Unknown Device?

External hard drives showing "Unknown" in Device Manager is a common disk error. Of all external disks, USB drives are the most likely to show this error. Here are a collection of possible reasons:

  • The external disk driver or USB controller becomes unstable or corrupt.
  • The selective suspend setting is enabled.
  • The motherboard driver is outdated.
  • The external disk or USB is damaged.
  • ...

Common Solutions to Solve External Hard Disk Showing Unknown Device

Here we will introduce you to 6 methods and fix external hard disk unknown device step by step. If you don’t know what to do, try the following methods.

Way 1: Restart Your System

Before starting to try the other methods below to solve the external hard disk unknown device error, you can choose to restart your computer and reconnect the device. Sometimes, this problem will disappear.  

Way 2: Reinstall USB External Disk Driver

1. Type device manager in the search box and select it from the results. Then, locate the problematic USB external hard drive.

2. Right-click on the unknown USB device and choose Uninstall device.

Unknown Device

3. Once the uninstallation process is complete, unplug the USB drive. Then, wait for approximately one minute and reconnect it. The driver should be loaded automatically. You just need to check if the USB drive shows up in Windows Explorer.

Way 3: Reinstall USB Controllers

1. Open Device Manager as explained in Way 2.

2. Expand the Universal Serial Bus controllers category, right-click the unknown USB drive and select Uninstall.

Universal Serial Bus Controller

3. Restart your computer after the uninstallation process. Your USB controllers will be reinstalled automatically.

Way 4: Disable USB Selective Suspend Setting

1. Type power plan in the search box and select Choose a power plan. Then, click on Change Plan Settings.

Change Plan Settings

2. Click on Change advanced power settings.

Change Advanced Power Settings

3. In the Advanced Setting tab, go to USB Selective Suspend Setting and select Disable. Finally, click Apply > OK to confirm it.

Disable USB Selective Suspend Setting

Way 5: Install Latest Motherboard Chipset Drivers

1. Consult your computer's documentation to determine the motherboard manufacturer.

2.  Visit the official manufacturer's website, find and install the latest motherboard chipset drivers. Contact the manufacturer for assistance if needed.

Last Resort: Initialize disk Showing as Unknown Device

If the external hard drive unknown device issue still exists, you can only initialize the disk. Although the process itself does not erase data, its further partitioning and formatting will. So it’s suggested to recover data from USB drive first. Let’s dive into it!

Part 1: Recover Data from Unknown USB Device

MyRecover is one of the most powerful data recovery software in Windows 11, 10, 8, 7, etc and Windows Server, which can recover data from health, problematic(eg: disk showing as unknown device) or damaged disk. It can be internal or external disk, USB drive, SD card, etc.

  • Has a high success rate and fast speed.
  • Scan the disk quickly and deeply with two advanced scanning methods and find out all the deleted or lost data completely.
  • Recover Word documents, Excel spreadsheets, PowerPoint presentations, photos, audios, videos, emails, webpages, and compressed files and 200+ file types.

1. Install and launch the powerful data recovery software - MyRecover on your Windows PC. Hover the mouse over the drive saved deleted files before, and click Scan.

Download Software Windows 11/10/8/7/Server
Secure Download

Select Partition To Scan

2. It will run two advanced scanning methods - Quick Scan & Deep Scan automatically and display all the found files on the selected disk. You can filter and preview files on the disk. Here are two methods:

  • Click Filter and select a file type, such as Documents. Then, type the file name or file extension in the Search for files or folders box.
  • Expand the Deleted Files, Recycle Bin, or Other Missing Files tab and check the deleted or lost files on the unknown device.

Scan Lost Data

3. Select all the deleted or lost files on the unknown device and click the Recover x files button. You will then be asked to select a location. Please select a new location instead of the original location.

Select Deleted Excel Files Click Recover


  • The restore button will display the number of selected files and their full size. You can use it to determine the integrity of the recovered files.
  • Saving the recovered files to original location may cause data corruption or further data loss.
  • You can recover data from disk showing as unknown device for free, up to 500MB in total. To recover all files on it, try advanced editions.

Except for recovering data from unknown device, you can also recover data from RAW disk, recover data from not initialized disk, recover files from a formatted hard drive, etc.

Part 2: Initialize Disk Showing as Unknown Device

After recovering data from unknown device, you will not worry about data loss anymore. You can then initialize disk in Disk Management.

1. Right-click on "This PC" and select "Manage" > "Disk Management".

2. Locate the disk showing “Unknown”, right-click on it, and select "Initialize Disk".


3. In the "Initialize Disk" window, select the MBR or GPT partition style and click "OK" to proceed.

Initialize MBR or GPT


You can easily fix an external hard drive unknown device with the possible reasons and corresponding solutions. Try 5 common methods first. If your problem still exists, try to recover data and initialize disk.

In addition, if you don’t want to lose any data on external hard drive, the best practice is to backup files on external hard drive or the entire disk automatically. Try free backup software for Windows - AOMEI Backupper Standard!

Ivy · Editor
Ivy is an editor of AOMEI Technology, she covers backup & restore,hard disk & partitions management and cloud files transfer and so on for AOMEI. She is an outgoing girl and enjoys helping people find solutions to their problems. She loves traveling, eating, reading and so on. She usually hangs out with friends at her leisure time.