This is probably a unique scenario to a consultant, but do ensure that each iOS device a user has under the same iCloud account is synced to the same tenant. Each are signed into with the same Apple iCloud account, but each at any time could be synced to different tenants. I have multiple test devices, two iPhones and one iPad.I did find one contact in iCloud that was not on the phone and that was myself! So I did not delete that one. So I was willing to delete everything on the phone as Exchange would put it back.

I made the assumption that all my contacts where mastered in Exchange.Here are some things I did to resolve these duplicates. So I have eight contacts and some of those where duplicates, some were missing on the device (only in iCloud) and some where different in Outlook Mobile from Contacts etc. I looked on my test iPhone to see if I could see any duplicates and to try and resolve – and given the conversations I was not suprised to find there were already a number of duplicates. Of the back of a few conversations recently on having duplicate contacts in the iOS platform because of syncing via multiple different routes or devices I decided to try to reproduce the issues and see what I could work out.

Delete duplicates in outlook contacts