Just wanted to say, I have the same problem as you - recently updating Piano V to version 1.1.0.205 caused my user presets to disappear from the available presets inside the Piano V interface. I did find that they were still apparently on my computer (Mac - Sierra) inside this folder - /Library/Arturia/Presets/Piano V/User - as basic data files. But even in seeing them, I couldn't import nor open them in Piano V.
With that said, I downloaded Piano V2 and installed the demo and it did see my previous user presets and it seems I can call up a version* of them inside Piano V2.
*it seems some preset data doesn't transfer over exactly. Specifically the EQ shows as flat on my end in V2 despite definite tweaks to the V1 version of the preset. And the mic settings also seem different. So they aren't my 'exact' presets' but they were close enough for me to use as a launchpad to tweak from? (maybe there's a VC5 preset updater that would see those original Piano V presets and update to V2 accordingly?)
Finally, I think it's a little unfair to chide someone about "it's your responsibility to make backups" since 'backups' in this case wouldn't actually solve this issue. This seems to point to an issue/bug with that version of the Arturia Piano V software as the presets don't seem to have been ''lost' (deleted), but rather it can no longer access them after the update.
