How do I stop email addresses duplicating in groups when adding a new member

Question

How do I stop email addresses duplicating in groups when adding a new member

Liz L 0

I have been adding new members to a group in outlook, it is duplicating their entry. So instead of showing 10 members, I now have 13, as 3 of them have been added twice.

I don't want those members getting the emails twice.

87986800 0 Reputation points

2026-11-12T11:18:16.3033333+00:00

1 answer

Your answer

87986800 0 Reputation points

2026-11-12T11:18:16.3033333+00:00

Answer 1

Emma1-N 15,005 Microsoft External Staff Moderator

Welcome Liz L,

I understand your concern about duplicate members receiving the same emails.

First, could you clarify whether you are using an Outlook contact list or a Microsoft 365 Group?

If you’re using a contact list, please try these steps:

Open Outlook.com
Select People from the left navigation pane.
Open Your contact lists and select the affected list.
Select Edit, check for duplicate email addresses, remove the extra entries, and save your changes.
For reference: Create, edit, or delete a contact list in Outlook.

Also, does this happen with every new member you add, or only with certain email addresses?

Looking forward to your update.

Liz L 0 Reputation points

2026-11-13T09:58:50.6033333+00:00

I am using a Microsoft 365 Group , it only happened on 3 of the 4 email addresses added. When I have deleted the duplicate address, it deletes both entries.