Depending on what client you are using, the experience may differ. The below suggestion assumes you are using server-side synchronization, as Outlook synchronization using the COM add-in has been deprecated.
If you use the Dynamics 365 App for Outlook and track contacts via the new Contacts add-in, you will be notified if your tracked contact duplicates an existing contact.
If you use the traditional Outlook client (COM add-in) and track a contact, you will not receive a duplicate detection notification, but the contact will not be created in CRM.
If you update an existing tracked Outlook client and by making the update the record now triggers a duplicate detection rule, the change will not synchronize to CRM.
So in the final two scenarios, it means that the tracking/synchronization is happening asynchronously/in the background. The new app is designed to do the duplicate check before flagging the contact to be tracked. Given that the legacy Outlook client is in maintenance mode, it is unlikely that this behavior will change in the legacy CRM for Outlook. Switch to the new app if it is available for you.
So what should you do if you tracked or updated a contact and the sync isn’t happening due to duplicate detection? Check the mailbox log. Go to Settings>>Email Configuration>>Mailboxes and open your mailbox record. Click on “Alerts.”
If a tracked contact was unable to be saved in CRM due to duplicate detection, you should see an alert log entry for that contact. Hovering over the alert should give you a yes/no choice of whether or not to save the duplicate in CRM.
