After you upgrade to Microsoft Lync Server 2013, when you edit contacts in Microsoft Lync 2010 or Lync for Mac 2011, you receive the following error message:
Cannot add, move, or remove contacts or groups at this time. Please try again later.
This issue occurs because, when the Unified Contact Store is deployed between Microsoft Exchange 2013 and Lync Server 2013, the Lync 2010 and Lync for Mac 2011 clients do not understand where it should update or save changes. Therefore, users who are enabled for the Unified Contact Store cannot change their contacts list from Lync 2010 and Lync for Mac 2011.
To resolve this issue, use Microsoft Lync 2013, Microsoft Outlook Web Access 2013, or Microsoft Outlook to change your contacts.
On Windows, to confirm if a user is enabled for Unified Contact Store, check the following registry key for a value of 2165. If the key is not present or does not have a value of 2165, the user is not enabled for Unified Contact Store and should be able to change contacts from a Lync 2010 client.
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