Duplicate Contacts (33,982) in my Outlook 365 OWA

Barry Walker 20 Reputation points
2025-04-21T07:34:48.1666667+00:00

Hi there,

help please. I have tried to remove my duplicates in Outlook many times. Tried in Outlook Classic, Outlook 365 and now in Outlook OWA, all to no avail.

However, i noticed this evening that I have 33,982 duplicates of only a few of very old contacts that will not be deleted no matter what I try.

I am not confident to use the 'script' process as will only likely make it worse :) Have you any way you can assist please? I end up with 1000's of duplicate accross my devices. Desktop, Surface Pro 9, my Samsung S24+ and now my work contacts when i synced them.

Outlook Management
Outlook Management
Outlook: A family of Microsoft email and calendar products.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Hien-L 1,060 Reputation points Microsoft External Staff
    2025-04-22T07:48:50.3966667+00:00

    Hi Barry Walker,

    Welcome to our forum!

    How did you delete the duplicate Contacts? Could you please describe the detailed operation?

    As I know: Deleting a contact in Outlook on the web removes it from all Outlook clients. However, if that contact was hidden in Outlook on the web, the contact card reappears until all hidden duplicates are removed. Please refer to the article Manage duplicate contacts in Outlook - Microsoft Support and try again.User's image

    In addition, you can also try to merge duplicate contacts using profile cards in Outlook on the web. More information: Merge duplicate contacts in Outlook - Microsoft Support 

    Hope it helps.


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