hi nickman,

I'm no LW expert but I am pretty confident that my answer will be valid nonetheless - no, you won't lose anything. At least, you shouldn't. I've upgraded to pro and updated several times and have had no such problems (the probs that I have had were download in progress related and seem to have been caused by a bug but is not relevant to your question). The upgrade reloads your existing files (Pro uses the same folder (i.e. Shared files) as basic) . Same as updates. LW will also automatically reload your existing downloads in progress when you upgrade/update.

but like I said, I'm no expert so you might want to wait for someone else's opinion. Is up to you...