There are a few contacts in our organization, which have the same e-mail address as user records, basically contacts of employees. This leads to duplicated To: and From: in e-mail and appointment activities, becuase Dynamics is matching those activities againt the contact and the user record. So there is a contact with the e-mail: employee1@contoso.com and a user with the same email address.
Now, I want to clean up by 'Deactivate'-ing the contacts, but the activities are still matched against the deactivated contact. So, deactivating does not solve the issue.
Next, I am thinking about deleting the contact, which has the same e-mail address as the user record in Dynamics, but I do not want to lose the activites which are linked to the contact. Is it somehow possible to delete a contact and keep his activities?