Consider the following scenario:
You sign in to Microsoft Lync 2010 in in an Exchange Server environment.
You change a contact’s name in the Contacts folder in Microsoft Outlook.
The change is updated to the Lync Contacts folder.
In this scenario, the contacts do not display in alphabetical order in Lync 2010.
Note If you update the view in the contacts list or you sign out and sign in to Lync 2010 again, the contacts will display in alphabetical order.
This issue occurs because Lync 2010 does not sort the contacts in alphabetical order again when a name is update from the Contacts folder to the Lync Contacts folder.
To resolve the issue, install the following cumulative update:
2791382 Description of the cumulative update package for Lync 2010: March 2013