If your USB drive files are hidden, you can only see the USB drive. Solved - USB Drive not Showing Files and Folders Method 1.

This usually happens when you plug the device into a public computer and the flash drive catches the virus from that computer. There are a few different types of viruses, but the biggest problem encountered is when folders become shortcuts and you can't access anything that was there before. If you click on the thumb drive with the right mouse button, go to Properties and see that there is space used, you will probably be able to recover your files. It turns out that they are still on the flash drive, but in hidden mode. Calm: you can recover your thumb drive and the files inside with a few tricks, without having to format it. It is not common for you to get a virus on the flash drive that hides folders and files, or turns them into shortcuts, leaving everything you have inside inaccessible.