When you attach your phone to a PC with a USB cable, you expect File Explorer to work the way it’s intended to work — copy, move, drag, drop and the like. As long as your PC is running Windows 7 or 8.1, that’s exactly what happens. But if you’re running Windows 10, watch out. You may end up deleting files.
Be careful with Android devices connected to a PC running Windows 10 via USB: harmless cleanup operations can cause photos and other files to be irretrievably lost. Almost all Android devices except the newer ones from Samsung are affected.