There are quite a few free instant folder hiding and locking utilities for Windows, but WinMend Folder Hidden would be the most easiest and feature-rich free file and folder locking utility of them all, the software allows users to hide and protect multiple files and folders using password on local partitions and removable devices, the best part is that the data once hidden remains invisible even when accessed from another operating system on the same computer or another machine.
The hiding/unhiding process is instant and can also be used to hide/lock files and folders on removable data storage devices like USB pendrives and memory cards.