10 Possible Reasons why your USB device is not recognized

Sometimes when you connect a USB device to your system it shows a nasty error message “USB device not recognized” or "Unknown device". I bet you know what I mean and everyone, at least once, experienced this problem on their computers.

There might be multiple reasons for the failure to recognize the USB device. We will review some of them:

1. Windows XP-based computer resumes from standby or hibernation

When you plug a USB device into a Windows XP-based computer immediately after the computer resumes from standby or hibernation, the computer does not recognize the USB device. There is a five-to-ten-second period when the selective suspend feature of the USB driver interferes with detection of the new USB device.

Resolution is simple. Unplug the USB device, and then plug the device back into the computer or hub.

2. USB Type

Your USB drivers are part of your main chipset drivers. The first time you install Windows, or if you have re-installed Windows from scratch since, you must load the motherboard main chipset drivers in order for Windows to have the proper info about your USB controllers, among other information.

If all your ports are USB 2.0 type only, and you try to plug the USB 1.1 device, you might have a permanent or intermittent recognition problem. If you have an older motherboard, with all or some ports being exclusively USB 1.1, your USB 2.0 will not be recognized as well. Newer motherboards are usually USB 2.0 for all ports, but they also should support any USB 1.1 devices.

3. Cold Reboot

This is my favorite troubleshooting approach, as it resolves about 40% of all the issues my customers are having with their computers. Shut down the computer regular way and patiently wait for it to power down completely. Remove power plug from the computer case. Some of the modern computers still keep the motherboard under residual power, even when computer is OFF. And we want to cut off all the power to PC in order to clear out any electronic glitches sitting in the electronic elements memory. Wait couple of minutes, and turn on computer in the reversed order.

4. USB port connections

Check if the device you try to connect is indeed connected properly. Note that it is possible to insert the USB connector upside down, forcing it inside. Be sure, that it is not the case.

If you notice that any device plugging will result in the same recognition failure, check the connector to insure that the pins are not bent or damaged. Note that the built-in (usually ftont) USB ports in your computer case might have a poor connection inside the computer itself. It's good to check the wire connections of USB port. The correct order of connection is Red, White, Green, and Black.

5. Power for USB devices

Some USB devices require extra power to work properly. A single USB connection, providing both data and power, might be insufficient to assure the proper device operation. If you can plug-in power cable, do that and you will decrease load on the device. You may also try choosing a different USB port. If you attempted to connect to USB hub, check if connection directly to USB port in computer makes any difference. You may also try a shorter (or more expensive) USB cable to improve the data transfer quality.

6. Device drivers

If windows is unable to recognize the device, the reason might be in missing or corrupted USB drivers. You can forcefully attempt to recognize the USB Device through Device manager.

Just follow these steps:

1. Click Start, click Run, type Devmgmt.msc, and then click OK. The Device Manager window opens.
2. Click to select your computer as the location for the scan.
3. On the Action menu, click Scan for hardware changes.
   Windows XP recognizes the new device.
4. Close the Device Manager window.

If this method does not resolve the issue, you may try to disable power management of the USB hub:

1. Click Start, click Run, type Devmgmt.msc, and then click OK. The Device Manager window opens.
2. Expand Universal Serial Bus controllers.
3. Right-click a USB Root Hub in the list, and then click Properties. The USB Root Hub Properties dialog box is displayed.
4. Click the Power Management tab.
5. Click to clear the Allow the computer to turn off this device to save power check box, and then click OK.
6. Repeat steps 3 through 6 for each USB Root Hub in the list.
7. On the Action menu, click Scan for hardware changes.
   Windows XP recognizes the new device.
8. Close the Device Manager window.

If this approach does not help either, you might uninstall all the USB related drivers through the Device Manager and let system find and recognize them again after computer cold reboot (unplug from power as was advised as well).

7. Removing Hidden Devices

If you plug the bad or incompatible USB device, the system will try to recognize it anyway and will attempt to fit the related drivers. However, if the process is not successful, it might corrupt your USB drivers, causing recognition problems for good USB devices. The following procedure will allow you to see ALL the drivers installed on your computer and remove all problematic from the configuration.

1. Click Start. Click Run. Type cmd and press OK.
2. Type set DEVMGR_SHOW_DETAILS=1 and press Enter.
3. Type set DEVMGR_SHOW_NONPRESENT_DEVICES=1 and Press Enter.
4. Type Devmgmt.msc and click press Enter.
5. Click View. Click Show hidden devices.
6. Click “+” to expand Imaging devices, Unknown devices and USB devices.
7. Are there any USB devices and unknown devices (including grayed out devices)? If so, please right click it and click Uninstall.

8. Removing Device Drivers

If all the attempts to uninstall the USB devices using the stored standard USB drivers failed, you drivers files might be corrupted. Follow the steps:

1. Remove all oem*.inf files =

·        Click start and click run then under the run line type in the command cmd.

·        In the command line, type in the following and press enter after each command:
cd \windows\inf
ren infcache.1 *.old
ren oem*.inf *.old
del C:\windows\setupapi.log

2.      Removing all entries under HKEY_LOCAL_MACHINE/Enum/USB that start with VID ==

Removing the VID entries from the registry will cause them to be redetected at restart.
CAUTION: If you have a USB keyboard or mouse, do not remove the VID entry for these devices, otherwise, Windows may not restart correctly.

·        Click Start and click Run. Type regedit and click OK. The Registry Editor window will open.

·        Go to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Enum\USB.

·        Highlight and delete all the VID_…. entries.

3.      Note that you will need the account permissions to delete the VID_entries. Follow the steps below:

• Right-click the key to be deleted, and then click Permissions. The VID_… Permissions window will open.
• With Everyone highlighted in the Group or User name section, select Full Control in the Permissions section.
• Click Apply, and then click OK.
  

4.      Turn off the computer.

Reconnect the USB device to the computer system: ==

• With the computer system turned off, reconnect the USB hub to the USB port.
• Restart the computer.
• A New Hardware Detected window should open and reload the drivers.

9. Virus/Trojan Infection

Since virus infection can be a real source for the USB device recognition failure, check your system for potential infection with virus/spyware/malware/adware. Note that some malware utilities intentionally hit the USB connection to decrease the user ability for the computer recovery.

10. Defective USB device

The last, but not the least, reason might be in the USB device itself. To verify its performance, check its recognition on another computer.