I recently had a challenge of recovering lots of folders hidden by a virus on a drive. Some virus always hide files and folders in an external drive and create a new folder with an extension like .exe, .lnk and so on just to fake users to a malicious act. The truth is, most anti-virus will detect this virus and remove it, but it doesn't return or restore the files and folders hidden by the virus. This is the 'headache spot'!