I've got version 9. I don't recall version 10 being worth the upgrade cost for me.
Question for you then.
I have a folder full of NEF files from my Nikon.
I edit some of these in DXO then export to disc (as jpegs to a folder i create and specify)
Others I just play about with but do not save or export.
When I go back to the original folder, there are some extra files with the LR logo (lightroom) and the suffix NEF.dop
I suspect these are the files I looked at and/or played with ?
I cant remember selecting this option or find where it is.
One would think the files if not saved would just remain as NEF files