USB is not recognized?

USB devices are becoming more and more common, almost all devices have a tendency to USB, such as printers, cameras, MP3, MP4, reading machines, but many times, we use USB devices is not so smooth. Often appear "Unrecognized USB device" prompts, then why this prompt, how to solve it

Reasons and Solutions:

1. Front USB cable Connection is wrong. This type of failure occurs when the USB cable on the motherboard corresponds to the front USB connector on the chassis, which is also quite dangerous, because the positive and negative connection is likely to cause the USB device to burn. So as far as possible with the chassis behind the USB interface, but also less use extension cord. It may also be a problem with the fracture, change the USB port to see.

2.USB interface voltage is insufficient. When the mobile hard disk is connected to the front USB port, it is possible that the system does not recognize the fault of the device. The reason is that the power of mobile hard disk is relatively strict, the front interface may not provide enough voltage, of course, inferior power supply may also cause this problem. The solution is to move the hard disk do not connect to the front USB interface, replace the inferior low-power power supply or try to use the external power of the hard disk box, if there are conditions.

3. Compatibility issues with the motherboard and system. Hehe This kind of fault is most famous is NF2 motherboard and USB compatibility problem. If you encounter this problem on the NF2 motherboard, you can install the latest NFORCE2 dedicated USB2.0 drivers and patches, the latest motherboard patches and operating system patches, or not, try refreshing the motherboard BIOS can generally be resolved.

4. System or BIOS problem. USB devices cannot be identified in the system when you disable USB in the BIOS or operating system. The workaround is to turn on the options associated with the USB device. is the boot press F2 or DEL key, into the BIOS, the Enable USB device select Enable.

5. Pull and plug to be careful, read and write must not pull out, or it may burn the chip. XP in the taskbar more than a USB device icon, open the icon will be shown in the list of U disk devices, choose to deactivate the device, and then you unplug the device, this will be more secure. In fact, to judge the software hardware problem is very simple, in another machine or another system to try it. Some small problems may be formatted with specialized software. And to remind everyone to choose FAT when formatting windows, do not select FAT32.

Prompt for unrecognized USB device repair

Troubleshooting tips as shown:

6. Unrecognized USB device: Unknown USB Device. A lot of people have encountered a problem, the so-called "unrecognized" for the operating system, or a problem with the driver, or a USB device problem, or the computer and USB device connection has failed, the solution is to solve the problem from the beginning. For different devices there will be different processing methods to understand the conditions of the USB device to work properly and some factors that may affect the normal operation of the USB device, can help solve the problem. Here are some conditions to ensure that your USB device works: (1) The USB device itself does not have any problems-can be tested on other computers to ensure that the normal work, (2) USB interface without any problems-can be connected to other USB devices on this interface test; (3) USB device driver has been properly installed, if there is a detailed description of the book of the USB device, be sure to carefully check the corresponding documentation, according to the instructions to install the corresponding driver; After Windows 2000 operating system to identify most USB devices, Windows 98 previous operating systems can install a USB device with its own drive or install a generic USB device driver.

7. The following are some situations that may affect the normal functioning of the USB device: (1) The USB device has failed (the same condition used before, and now there is a problem);(2) USB interface has problems, such as a. USB Front Interface Polarity connection, this may cause the USB device burned, so be sure to carefully look at the motherboard instructions, to prevent access to the wrong; B. The interface voltage is insufficient, some mobile hard disk often have such problems, the host behind the USB interface is usually more reliable than the front USB interface; C. Motherboard and operating system compatibility problems, install the latest motherboard driver to maximize the avoidance of such problems; USB devices are disabled in D.bios and may be resolved by changing the corresponding settings in the BIOS; E. Operating system problems can be solved by reinstalling the operating system; (3) There is a problem with the USB driver: If you suspect that the driver has a problem, you should ensure that the latest driver for the appropriate model of the device is installed or that the operating system does not require a special drive, and that the latest driver can be found by the home page of the manufacturer of the online device. When there is a problem with the USB device, in addition to looking for a solution based on the actual error message, it is also important to look closely at the specific brand, model, manufacturer of the USB device, including this information when searching for results, and to find the solution more easily. Like some plug-and-pull effort requires a frequently connected USB device temporarily fails, the operating system is constantly "unrecognized USB devices" such as annoying prompts, you can temporarily close the Universal Serial Bus controller in the appropriate USB port or prohibit the corresponding USB device.

8. About the unrecognized USB device after the computer setup is inserted, will be in the lower right corner of the computer is trying to connect some of the USB device information, and sometimes pop-up dialog box to allow users to choose, some users have not seen the point is not, or because some of the computer's initial setup problems, prohibit some of the USB features. Solution: Right-click "My Computer", select "Properties"-"Hardware"-"Drive Signature", choose "Ignore" here, click "OK". Then plug in the MP3, or not, and then right-click "My Computer"-"Properties"-"Hardware"--"Device Manager", find "Universal Serial Bus Controller", right-click, and "Scan for hardware changes."

9. The voltage problem of the equipment itself as a result of the current MP3 trend is to reduce costs, so the companies continue to adopt new programs, new master, new Flash chip, not to say that these new things on Jerry, the problem is that these new things often require long-term debugging to achieve the best, But the market situation can only allow MP3 factory test can be in a computer interface on the machine to put into production, so often appear not online, off the disk phenomenon. In this case, users need to try more than a few times, plug different USB interface, separate with a good quality USB cable (generally thicker the better, better copper than iron), and then ensure that the MP3 power supply normal (with the charger to fill the electricity and try again).

10. The system error "Unrecognized USB device" failure phenomenon: the use of U disk when the computer unexpectedly power off, reboot after the U disk can not be used normally, plug the system on the error "Unrecognized USB device." The same error message will be prompted with other USB interface devices that used to be normal. Plug the USB device into the other USB connectors on your computer to work properly. Analysis failure: From the phenomenon, the USB device and motherboard interface are not damaged, suspected to be accidental power loss caused system setup error. Problem handling: Enter the Add and Remove Hardware window from the Control Panel, remove all USB devices, and reinstall the USB device drivers that you need to use. Restart the computer, U disk and other USB devices plug in the original fault interface to work properly. Unrecognized USB device-laptop hard drive failure and removable hard drive, plugged in front USB connector, unrecognized.

11. In this case, a large part of the problem is power supply. Because the USB hard disk in the work also need to consume a certain amount of electricity, if directly through the USB interface to take electricity, it is likely to appear power supply. As a result, almost all mobile drives come with a separate external power supply or a PS2-turn interface that is powered by a keyboard. At this time as long as the prior connection to the external power supply or through the PS2 to connect with the keyboard, to ensure that the mobile hard disk to provide enough power after the test, then should be normal use of it. It is important to note that it is recommended that you make sure that you have enough power before using a removable hard drive, or you may be damaged by a lack of power. For a friend who has never used a USB add-in, it is possible that the system cannot detect a USB hard drive even if the driver is properly installed, mainly because the default CMOS port on the motherboard is turned off, and if it is not set to open, Then Windows naturally cannot detect the removable hard drive. To solve this problem, we can reboot, enter the CMOS Setup window, and in the "Pnp/pci CONFIGURATION" column, "Assign IRQ for USB" is set to "Enable", This allows the system to assign an available interrupt address to the USB port. It is also possible that the USB interface type does not match, causing the removable hard drive to be unusable. For example, the computer configured USB interface is 1.1 standard, and the purchase of the mobile hard disk is the USB 2.0 standard interface, which requires connecting the computer and mobile hard drive connector must support the USB 2.0 standard. Because a high-speed mobile device is plugged into a low-speed hub, the device may not be installed properly, and some friends use a USB drive while using a mobile hard disk, which makes it easy to use the 1.1 standard connector that comes with the USB 2.0 standard, which results in the correct identification of the mobile hard drive. This failure can be resolved simply by replacing the connector with the USB 2.0 standard.