How to delete all outlook and teams contacts

Refer to https://learn.microsoft.com/en-ca/answers/questions/5839082/how-can-i-bulk-delete-thousands-of-my-contacts-in and https://covve.com/how-to/how-to-bulk-delete-contacts-in-microsoft-teams

For New Outlook for Windows with a personal Outlook.com / Hotmail / Live account, the most reliable way to clean up a very large contact list is to manage the contacts directly in Outlook.com > People, since this is the primary contact store that New Outlook syncs from.

Before deleting anything, export your contacts to a CSV file so you have a backup.

Important: Deleting contacts from Outlook.com removes them from all Outlook apps that sync with this account.

Steps:

1. Sign in to https://outlook.live.com using the same Microsoft account.
2. Open People.
3. Delete the contacts in multiple rounds/pages. With very large lists, Outlook.com may not allow deleting everything at once, select all contacts on the current page, delete them, then repeat until the list is cleared.
4. Once the old contacts are gone, allow New Outlook some time to sync.
5. Use Import contacts to bring back only your smaller CSV file (for example, your ~100 contacts).

If the contacts are already gone on the web but still appear in New Outlook, close and reopen the app, then sign out and back in to force a refresh of the sync.

If you also have Classic Outlook for Windows installed, bulk deletion there is often faster for very large contact lists (for example, selecting all contacts at once and deleting them). This is optional, but can speed things up if you’re comfortable using it.

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hth

Marcin