The Editor's Note: USB flash drive supplier Shenzhen lenrich technology Co., Ltd. reminds you friendly that the following information is for reference only.

 
       If USB flash drive can’t be identified by the computer because of its system or system built-in drivers, which you can repair with the following methods.
1. Press F8 when boot to enter into safe mode then exit to restart or shut down then boot, you can enter the normal mode (registry repair).
2, if the fault remains, please activate the computer system restore to revert the time without the fault to repair (if the normal mode furbishing fails, please boot then press F8 into Safe Mode to use System Restore).
3, if the fault remains the same, using the system disk to repair. Open the command prompt then enter SFC / SCANNOW, press “Enter” (a space between SFC and /), insert the original system disk to repair the system, the system will automatically restore contrastively.
4, if the fault remains the same, set CD-ROM as the first boot device in the BIOS then insert it into system disk, press “R” button for "repair installation".
5, if the fault remains, it is recommended that reinstalling the operating system is necessary.
 
      Fault diagnosis is as follows when USB flash disk inserted into computer which clues "unrecognized equipment":
Step 1: If USB flash disk inserted into the computer which clues "unrecognized equipment", that illuminates the power supply circuit of USB flash disk is normal. Then we need to check the whether there’s faults in the USB interface circuit of USB flash disk.
Step 2: If it’s normal, faults may be on clock circuit (It’s the out-of-synchronization between USB flash drive clock rate and the computer). In the following we need to detect the crystal oscillator of the clock circuit and the resonant capacitor.
Step 3: If the clock circuit remains normal, it may be the bad work of MPU. Check the power of MPU, if it’s ok, then there must be damage on MPU, which will be solved by a replacement.
 
       There is also another reason, the insufficient power supply of the USB flash memory interface. When there’re too many peripherals connected into USB interface, insufficient power supply will happen. Change to electriferous USBHUB or the USB –to- PS / 2 turning joint. While it still may be WindowsXP’s power-saving mode by default, resulting in insufficient power supply of USB interface, causing the intermittent failures. Right-click My Computer / Properties / Hardware / Device Manager, then double-click "Universal Serial Bus controllers" ,several "USB Root Hub" appear .Double-click any one, open the Properties dialog box, switch to the "power management" tab, and remove "Allow the computer to turn off this device to save power", click OK to return Restart the computer after modifying every USB RootHub. USB flash drive will be able to resume stable operation, while at the same time the set the frequency as low as possible.
 
     If drive label of the USB flash memory still show no sign, the solution is: right-click My Computer / manage / storage / disk management, then right-click "Removable Disk" ," click the" Change Drive Letter and path "option of shortcut menu, and then click " Add "button, then select" assign drive letter ",simultaneously select the appropriate drive letter from the drop-down list, click ‘OK’ to finish. Finally, open “My Computer”, you can see the drive letter of USB flash memory.