I have encrypted my USB drive in Windows 8 using BitLocker, but I noticed after unlocking it, it does not give me the option to "Turn BitLocker On"? Any ideas as to why that is?
When you unlock it, it will remain unlocked until you log off or restart the computer next, then it will be automatically locked again. If you like, you could use the tutorial below to lock the drive again without having to log off or restart the computer.