Sorry to revive an old thread, but I am having this same issue also. My ADIF that I upload monthly contains new records, as well as the same records from previous months. Having read all of the documentation about Logbook V2, I didn't expect to see all the duplicates in my logbook. As far as I can tell, the duplicate records match verbatim. Is it possible the dupe check isn't working? I tested this by importing the exact same ADIF a second time to see what happens... where every single QSO record should have been marked as a 'dupe', the import log shows 0. I'm confused.