First, we should look at the U disk above the write protection switch is open, the switch and the previous use of the same floppy disk principle. If you have a switch, be sure to turn it on.
Second, check the root directory of the U disk number of files to achieve the maximum, the usual format should be 256. If you do not reach 256, continue to see the next step.
Third, on "My Computer" right-click--> properties--> Hardware--> Device Manager--> Universal Serial Bus controller to see if the items in this item are all normal, and if you have an abnormal update the driver.
Four, after the test found that the U disk to another machine can be used normally, indicating that the fault is not the U disk itself, and on that machine. At this point to the U disk format, conversion format and other operations will not work.
Solution steps:
1, start--> run-->regedit--> OK, enter the registry.
2, view Hkey_local_machinesystemcontrolset002control and Hkey_local_ Whether there is a Storagedevicepolicies subkey in the Machinesystemcontrolset001control two, and whether there is a Writeprotect value in the subkey, and if so, change the value to 0 and then skip to step 5th; If not, proceed to the next step.
3, view hkey_local_machinesystemcurrentcontrolsetcontrolstoragedevicepolicies if no storagedevicepolicies the item, then new ( Right-click on control--> New--> Item, rename new item to storagedevicepolicies)
4, in the right column to establish a new DWORD value, named Writeprotect, the value of 0 5, restart the computer after inserting a U disk, back to normal.
Careful friends will generally find u disk switch lock, u disk driver is normal and so on. And most of the Friends of the U disk is written to protect because the file is artificially changed, resulting in the normal storage of reading, at this time we need to adopt the fourth way to modify the registry to skillfully solve. After testing, the above four methods of one round detection, the basic can let your U disk restore normal operation. U disk is written to protect friends, but also to try the top of the coup.