Click on "Start" -->Run --> type cmd and click on OK.
Here I assume your pendrive letter as G:
Enter this command.
attrib -h -r -s /s /d g:\*.*
You can copy the above command --> Right-click in the Command Prompt and paste it.
Note : Don't forget to replace the letter g with your pen drive letter.
Now check for your files in Pen Drive.
Copy your files and folder into somewhere save and then format your pendrive. After that, copy back your files and folder back into your pendrive.