It sounds as if you have a faulty USB drive, depending on your Operating System, MS Windows / Linux, uninstall the USB drivers under device manager which could be found in the control panel on Windows XP/Vista/7, restart the computer and reinstall the driver's if they don't install back by themselves. But before you start try using your thumb drive on another computer. If you get the same problem, try to reformat the thumb drive, but before you do, be aware that all your information will be lost, and will not be able to be recovered without the appropriate recovery tools.
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It sounds as if you have a faulty USB drive, depending on your Operating System, MS Windows / Linux, uninstall the USB drivers under device manager which could be found in the control panel on Windows XP/Vista/7, restart the computer and reinstall the driver's if they don't install back by themselves. But before you start try using your thumb drive on another computer. If you get the same problem, try to reformat the thumb drive, but before you do, be aware that all your information will be lost, and will not be able to be recovered without the appropriate recovery tools.