Whats ventoy? Ventoy is a free and open-source utility used for writing image files such as .iso, .wim, .img, .vhd(x), and .efi files onto storage media to create bootable USB flash drives. Once Ventoy is installed onto a USB drive, there is no need to reformat the disk to update it with new installation files; it is enough to copy the .iso to the USB drive and boot from them directly.