1. The front USB cable is connected incorrectly. This kind of fault will happen when the USB cable on the motherboard is connected to the front USB interface on the chassis, which is also very dangerous, because the positive and negative connection is likely to burn out the USB device. So try to use the USB interface on the back of the chassis and use less extension cables. There may be something wrong with the fracture. Look at the other USB port.

2.USB interface voltage is insufficient. When the mobile hard disk is connected to the front USB port, the system may not recognize the device. The reason is that the power of the mobile hard disk is relatively large and the required voltage is relatively strict, and the front-end interface may not provide enough voltage. Of course, inferior power supply may also cause this problem. The solution is not to connect the mobile hard disk to the front USB interface, replace the inferior low-power power supply or try to use the hard disk box with external power supply, if possible.

3. Compatibility between motherboard and system. Hehe, the most famous fault is the compatibility between NF2 motherboard and USB. If you encounter this problem on the motherboard of NF2, you can first install the latest USB2.0 driver and patch of nForce2, the latest motherboard patch and operating system patch, or try to refresh the BIOS of the motherboard, which can generally be solved.

4. System or BIOS problems. When you disable USB in BIOS or operating system, the system will not recognize the USB device. The solution is to turn on the options related to USB devices. That is, press F2 or DEL to start, enter the BIOS, and select Enable usb device.

5. Be careful when plugging and unplugging. Never unplug it when reading or writing, or it may burn the chip. There are more USB device icons in the taskbar of XP. When you open this icon, USB devices will be displayed in the list. Choose to disable this device, and then you can unplug it, which will be safer.

In fact, judging software and hardware problems is very simple. Just try it on another machine or another system. Some minor problems may be formatted with special software first. And remind everyone to choose FAT instead of FAT32 when formatting under WINDOWS.

Solution:

Computer settings

After insertion, some information that the computer is trying to connect to this USB device will pop up in the lower right corner, and sometimes a dialog box will pop up for the user to choose. Some users clicked No without seeing it clearly, or some functions of USB were banned because of some initial setup problems of the computer.

Solution: Right-click my computer and select Properties-Hardware-Drive Signature. Select Ignore here, and then click OK. Then plug in MP3. If you still can't connect, right-click My Computer-Properties-Hardware-Device Manager to find the USB controller, right-click and scan for hardware changes.

The voltage problem of the equipment itself

Because the current trend of MP3 is to do everything possible to reduce costs, the company constantly adopts new schemes, new controllers and new FLASH chips, which does not mean that these new things will cut corners. The problem is that these new things often need to be debugged for a long time to do their best, and the market situation can only allow MP3 factory testing to be put into production on one interface of a computer, so disconnection and disk dropping often occur.

In this case, users need to try several times, plug in different USB ports, and match a good quality USB cable separately (generally, the thicker the better, the copper is better than the iron), and then ensure the normal power supply of MP3 (try again with a charger).

The system reports "Unrecognized USB device"

Fault phenomenon: The computer accidentally loses power when using the USB flash drive, and the USB flash drive can't be used normally after restarting. After insertion, the system will report "Unrecognized USB device". Using other USB interface devices that can work normally will also prompt the same error message. Plug USB devices into other USB interfaces of the computer, and they can all work normally.

Fault analysis: Phenomenologically, the interface between USB device and motherboard is not damaged, and it is suspected that the accidental power failure caused the system setting error.

Solution: Enter the window of adding and deleting hardware from the Control Panel, delete all USB devices and reinstall the required USB device drivers. Restart the computer, and USB devices such as USB flash drive can work normally when plugged into the original fault interface. Unrecognized USB devices-notebook hard disk failure and mobile hard disk, plugged into the front USB interface, are unrecognizable.

For friends who have never used a USB external device, even if the driver is installed correctly, the system may not be able to detect the USB hard disk. This is mainly because the default CMOS port of the motherboard is closed. If it is not set to the open state, then Windows naturally cannot detect the mobile hard disk. To solve this problem, we can restart, enter the CMOS setting window, and set the item "Assign IRQ to USB" to "Enable" in the column of "PNP/PCI configuration", so that the system can assign available interrupt addresses to USB ports.