This app did remove the majority, but not all, of the duplicates from 3,000+ contacts, but, at the same time, it completely removed each and every contact listed in my groups. Fortunately, I was able to restore my contacts using Gmail, which, at the same time, restored all my Groups. (While I was in the Contacts section of Gmail, I cleaned out my duplicates using Gmail’s “find duplicates” feature.) Then using the "Contacts Sync for Google Gmail” app I was able to restore Contacts in iCloud.

All the app does is crash. It started out working fine. It found all the duplicate contacts. I began merging them one by one. However, I did a quick look through several contacts and then decided to merge all at once. Within a couple of minutes, it crashed. I can open the app and tell it to start scanning. It's get to the 50% point and crashes every time now. I can't get it to work. I've tried uninstalling and reinstalling and crashes. While it was only 99 cents, a waste of my 99 cents at this point.

This app still crashes on the All Merge option. Would be fine to go through every contact to merge but I have hundreds and all seem to have a duplicate. Going one by one would take days... I see this complaint all the way back over a year and it is still not fixed. That needs to be said. If you buy this app they do not update to fix things.

Love the duplicate phone and email options. I have about 800 contacts. Removed all dups, no issues. I don't use groups, so can't say to those that had issues in this reviews.