Outlook group contact reappearing after removal

Try this:

1: Confirm Group Type

Is this a local contact group (a distribution list saved in the user's mailbox) or a Microsoft 365 Group?

• If it's a local contact group (aka personal distribution list), it’s stored in the user's mailbox and editable only by them.
• If it's a Microsoft 365 Group, changes must be made via the admin center or PowerShell.

2: Purge Auto-Complete and Suggested Contacts

Outlook may be auto-repopulating the contact from its cache or Suggested Contacts.

• Outlook Desktop:
  Go to File > Options > Mail > Send messages
  → Click Empty Auto-Complete List
• OWA (Outlook Web App):
  Settings > Mail > Compose and reply
  → Clear the auto-complete cache

Also, when typing the group name, delete any cached suggestions that include the old contact.

3: Check for Hidden Sync Sources

Sometimes the contact is being pulled from:

• GAL (Global Address List): If the user was cached in GAL before deletion, it may take time to purge.
• Outlook Contacts: Check if the terminated user exists in the user's Contacts folder.
• Mobile Sync: If the user syncs Outlook with a mobile device, the contact may be reintroduced from there.

4: Recreate the Group

1. Create a new contact group from scratch.
2. Manually add the current members.
3. Delete the old group.
4. Test sending to the new group.

5: Admin-Level Cleanup (if it's a Microsoft 365 Group)

If the group is managed centrally:

• Use Microsoft 365 Admin Center or PowerShell to remove the contact:

Remove-UnifiedGroupLinks -Identity "Group Name" -LinkType Members -Links "user@domain.com"

• Confirm the user is fully purged from Azure AD and not lingering in a soft-deleted state.