No biggie answering for me, bill_s. I’m always up to getting things done, even when I’m not around!
Yes, if you reformat your drive, you will lose everything on it. I was rather lucky because I had an empty drive that I tested with the WD TV Live. However, if you do use the utility I mentioned, of which I only used once, it should be able to repartition your drive without losing your data. But, the caveat being, you should have a backup of all your data to begin with, just in case if the drive does go squirrelly on you.