O.L. Virtual Hard Disk Attach
This application allows you to create and attach virtual hard disks. This can be useful in these situation:
-You have important files on your USB flash disk you don’t want to let viruses corrupt, because you can copy OLVHDA to your USB stick, and when you want to read the files in the infected laptop, use the “Read only” feature when you want to attach the disk.
-You want to encrypt some of your files on your partition using Bitlocker.
-organize important file into VHDs.
-Provide a simple way to deal with VHDs.
Q: How do I secure my virtual disk?
A: You can use BitLocker!

Q: The application is not working on my USB drive!
A: Make sure that it has NTFS file system, if it’s already FAT, make sure that the application is inside a folder (isn’t located directly in the partition root).

This video shows how to use OLVHDA to mount virtual disks.