You may also need to hover over the contact categories on the left to expose "Other Contacts" at the bottom, where I had an additional 9200 duplicates for my wife. And, it can only process 2500 at a time, so if you have this situation, you may need to run the Find and Merge several times in succession.
Wish I knew how to make it not do this in the first place. Maybe there was a bug at one of my recent reinstalls....