Connect the USB pen drive or flash drive to PC. Open Windows Explorer > Go to Tools > Folder Options > Go to View Tab > Check "Show Hidden Files". This will make sure that the files and folders are not in hidden mode.
Next, click on Start Menu -->Run --> Type cmd and press Enter.
To make the pen drive data showing, type the commands:
attrib -h -r -s /s /d k:\*.*
press Enter. Here, you need to replace "K" with your pen drive letter.