Hi welcome to the forum, not a clue how he managed to delete your recordings. About the only way to do that in one, is a hard disk format. Firstly to watch a recording from a usb stick it has to be in a specific format with 3 files, a programme called AV2HDR can create these. Assuming the right format you put in the usb stick. When you see the message on screen, press media and then the red button. Use the arrow keys to change the selected device at the top of the screen to usb. The recordings will be listed just like the internal ones are.