Assume that the Unified Contacts Store is enabled for users in a Microsoft Lync Server 2013 and Microsoft Exchange Server 2013 environment. After the users' contact data is migrated to the Unified Contacts Store in Exchange Server 2013, the users cannot edit the contact data by using Lync 2010 or Lync 2010 Mobile.
When the users sign in to Lync 2013 for the first time, the users' contact data is migrated automatically to Exchange Server 2013.
If the users' mailboxes are not hosted in Exchange Server 2013, this issue does not occur.
To edit the contact data in the Unified Contacts Store, use Lync 2013, Microsoft Outlook 2013, or Outlook Web App 2013.
This behavior is by design.
For more information about the Unified Contacts Store, go to the following Microsoft website: