When your computer displays the message "Unknown USB Device (Descriptor Request Failed)", it indicates that the USB device cannot be properly recognized by the system. This issue can stem from various causes such as poor hardware contact, driver malfunctions, or abnormal system settings. Below is a step-by-step solution to help you quickly diagnose and fix the problem.
In many cases, simple physical checks can resolve the issue. It is recommended to begin with the following steps:
Replug the USB device: Unplug the device from its current port and wait 10 seconds before reinserting it. When plugging and unplugging, apply moderate force to avoid unstable connections caused by oxidized contact strips.
Change the USB port: Try inserting the device into another USB port on the computer (especially the rear ports, which provide more stable power supply). If using a USB hub, connect directly to the computer's native ports for troubleshooting.
Test other devices: Insert other USB devices such as USB drives or mobile phones into the same port to determine if the problem lies with the port or the current device. If other devices also fail to be recognized, the port may be physically damaged.
Restart the computer: Some temporary system glitches can cause USB recognition issues. After restarting, the system will reload the USB controller drivers, which may restore normal functionality.
If basic troubleshooting fails, you can fix USB driver or controller issues through Device Manager as follows:
Open Device Manager: Press the Win + X key combination and select "Device Manager"; or press Win + R, type "devmgmt.msc", and press Enter.
Locate the problematic device: Expand the "Universal Serial Bus controllers" option. If a device with a yellow exclamation mark appears in the list (usually named "Unknown USB Device"), this is the faulty device.
Uninstall and reinstall the device:
Right-click on the problematic device and select "Uninstall device". In the pop-up window, check "Delete the driver software for this device" (if available) and click "Uninstall".
After uninstallation, right-click on "Universal Serial Bus controllers" and select "Scan for hardware changes". The system will automatically reinstall the driver.
Update USB controller drivers:
If the above steps do not work, right-click on "USB Root Hub" under "Universal Serial Bus controllers" (there may be multiple) and select "Update driver".
Choose "Search automatically for drivers" to allow the system to find and install the latest drivers. If the computer is not connected to the Internet, you can download the corresponding USB drivers from the motherboard manufacturer's official website in advance for manual installation.
Some computer power management strategies can cause unstable power supply to USB ports, which can be resolved through the following settings:
Open Device Manager, expand "Universal Serial Bus controllers", and find "USB Root Hub" (if there are multiple, each needs to be set individually).
Right-click on "USB Root Hub", select "Properties", and switch to the "Power Management" tab.
Uncheck "Allow the computer to turn off this device to save power" and click "OK".
Repeat the above steps for all "USB Root Hubs" to prevent the system from turning off USB power for energy saving.
If the above methods still do not solve the problem, further investigation into system or hardware issues is required:
Check for system updates: Press Win + I to open Settings, go to "Update & Security", click "Check for updates", and install all available system patches. Microsoft regularly releases updates to fix USB-related system vulnerabilities or compatibility issues.
Test the device on another computer: Connect the faulty USB device to another computer. If it still cannot be recognized, the device itself is damaged (such as a faulty USB drive chip or a broken mobile phone data cable) and needs to be repaired or replaced.
Diagnose hardware faults: If all devices connected to the same computer show this error, there may be hardware problems such as a damaged USB controller on the computer's motherboard or a faulty southbridge chip. In this case, it is recommended to contact professional maintenance personnel for testing, or try adding new USB ports through a USB PCI-E expansion card.
System restore or reinstallation: If the problem occurred after recently installing software, drivers, or making system settings, you can restore the system to a previous working state through "Control Panel → Recovery → System Restore". If the system is severely damaged, consider reinstalling the operating system (back up important data before reinstallation).
The "Unknown USB Device (Descriptor Request Failed)" error is common but can mostly be resolved through basic troubleshooting, driver repairs, or setting adjustments. It is advisable to try the above methods in order from "simple to complex": first check physical connections and ports, then repair drivers and power settings, and finally investigate system or hardware faults. If you have difficulty handling the problem yourself, seek professional technical support promptly to avoid exacerbating the issue due to incorrect operations.
