Riva Cloud and Riva On-Premise's Default Behaviour
When a user deletes a Riva-synced contact from an email client address book,
Changing the Second Default Behaviour
You can change the second default behaviour for syncing with Dynamics CRM 2011 or higher versions. After the change is implemented, if a user deletes a CRM contact from an email client and later updates the contact in the CRM, Riva does not sync a new copy of the contact to the user's email address book.
Implementation for Riva Cloud
Implementation for Riva On-Premise
To prevent syncing an email-deleted contact back from the CRM to the email address book: