Outlook duplicate contacts

In Classic Outlook, there is no automated process to remove duplicates after they already exist. For many duplicate contacts, the supported way is to export the contacts, re-import them with duplicate checking, then move contacts back and choose whether to add or update duplicates.

Steps for a large number of duplicate contacts:

1. Open People in Classic Outlook.
2. Right-click the current Contacts folder and select New Folder.
3. Name it something like Duplicates.
4. Go back to the main Contacts folder.
5. Press Ctrl+A to select all contacts.
6. Move them to the Duplicates folder:
   • drag and drop, or
   • press Ctrl+Shift+V and select the Duplicates folder.
7. Confirm the main Contacts folder is now empty.
8. Go to File > Open & Export > Import/Export.
9. Select Export to a File.
10. Select Comma Separated Values (Windows).
11. Select the Duplicates folder.
12. Save the CSV file and select Finish.

Import back without duplicates:

1. Go to File > Open & Export > Import/Export.
2. Select Import from another program or file.
3. Select Comma Separated Values (Windows).
4. Browse to the CSV file that was created.
5. Select Do not import duplicate items.
6. Choose the main Contacts folder as the destination.
7. Select Finish.

Merge or keep the right version:

1. Open the Duplicates folder.
2. Press Ctrl+A to select all contacts there.
3. Move them back to the main Contacts folder.
4. When Outlook detects a duplicate, choose:
   • Add new contact if it is not really a duplicate.
   • Update information of selected contact if it is a duplicate and the existing contact should be updated.
5. To apply the same choice to all duplicates, select Update All.
6. When finished, delete the Duplicates folder.

If there are only a few duplicates, a faster option is:

1. Open People.
2. On the Home tab, in Current View, switch to Phone view.
3. Hold Ctrl and select duplicate contacts.
4. Press Delete or Ctrl+D.

Related import behavior in Classic Outlook:

• Replace duplicates with items imported overwrites existing Outlook contact data with the imported CSV version.
• Allow duplicates to be created keeps both copies.

• Manage duplicate contacts in Outlook | Microsoft Support
• [Classic Outlook](https://support.microsoft.com/outlook/people/manage-duplicate-contacts-in-outlook)
• [Classic Outlook](https://support.microsoft.com/outlook/people/import-or-export-contacts-in-outlook-using-a-csv-file)