First rename the folder from .HIDE to HIDE. (The dot at the beginning makes the folder invisible in Linux (which is the operating system in Android).
Then the ROM probably has to be rooted to see anything in the folder, because it's probably a system folder. If the ROM isn't already rooted, rooting it could overwrite files that are marked 'deleted'. (Files don't get deleted, they just get marked deleted, and the space they sit in is marked as usable.)
And why, unless your company requires it, would you be running Knox anyway? (You have to download Knox - what's in the phone when you get it is just a stub, it's not Knox.) If the company requires it, and you fool around in there, it could mean your job. But if it's your personal phone, there's no reason to download Knox.