You accidentally delete a tracked contact in Outlook and empty your deleted items folder.
You try to recreate the contact and re-link it to the contact in Microsoft Dynamics CRM, but it creates a duplicate contact.
The contact still exists in the IDMappingTable and is marked as IsDeletedlocally = True.
Re-configure Microsoft Dynamics CRM for Microsoft Office Outlook and sync with Microsoft Dynamics CRM again. Contacts that were deleted in Outlook will be added back to the Outlook contact list.