In my case that has occurred several times because I have multiple e-mail providers (gmail, Exchange, etc.). The first time I got a smart phone it copied the contacts from my Exchange account to the device and then gmail copied them to my gmail account from the device and, boom, duplicates.

I'm sorry to say that I haven't found an easy way to De-dup them. I manually go through and delete the extras.

I really hope someone else has a better way.

 

You havent said whether the contacts are in your phone too? First try doing an import of all the contacts to your device so that they are saved in your phone. Then, there's a choice to only show phone contacts or use phone contacts, while still contacts auto-backup is on. When you do this, you will only have phone contacts, then when you add any extra contacts, they will be backed up to Google.

 

Do a search for "Duplicate Contacts" in the Play Store.

 

I used to run into this problem a lot early on with my other android devices. I did the duplicate cleaner app a while back. I uploaded all of my contacts to my Google account. Now I only add new contacts to that account.

Among other things, it makes it incredibly easy to move from one android device to another.

 

Had this happen with a phone a few years ago. I had contacts on Google, and on my phone. So I exported all contacts from my phone, deleted all contacts from my phone (which also deleted them from Google),then imported the export list from my phone into Google and then there's a function in Google to merge duplicate contacts. It sounds like a lot of steps, but it wasn't much work. And in the end I had exactly what I wanted - all contacts in Google and Google only.