Hi there Welcome to the WD Community!
What is the WD External Drive that you have in mind (model number)?
- Using an external drive as a boot drive depends on the OS itself if it supports booting from a USB drive (if the drive that you have in mind uses USB connection).
- You could check out Windows To Go options if you prefer this OS.
- You should be able to install Linux distros on external drives fairly easily. Here’s an example.
- I have personally used this at a time when I didn’t have an internal drive in my laptop.
- The Linux OS should be working completely fine from an external HDD or an external flash drive.
- The version depends entirely on your preferences and needs. What are you planning to use the OS for?
- If you give more detailed information regarding the type of usage, specific hardware in your system, specific applications, etc. we may be able to provide better suggestions.
Thanks for posting and I hope this is helpful! Feel free to ask any questions you may have!