MultiOS-USB is a tool that addresses advanced users who want to be able to operate with multiple ISO files when reinstalling the operating systems. The tool can come in handy if you are experimenting with various software or system features on various versions of the same OS, for instance.

It is important to note that the tool requires additional image writing software, as you need to write ‘image.img’ to disk first. The next step implies running diskmgmt.msc and accessing the unallocated space - via right-click - to configure the details of  the new volume, namely size, filesystem and label. If you reached this point, then you can safely proceed to unpack the files.zip to the new disk you just created, copy the ISO files and boot the PC from the USB.

Some of the noteworthy features of the application include BIOS and UEFI support, secure Boot support, loading UEFI drivers, launching various bootloaders including .EFI executables, booting from ISO, customizing ISO boot menu as well as exFAT filesystem support. As far as accessing the ISO files is concerned, you will be happy to learn that the tool comes with autodetect on a loopback function, so the new ISO files can be immediately identified.