Consider the following scenario:
You update Microsoft Lync 2010 to version 4.0.7577.314 by installing the update that is mentioned in Microsoft Knowledge Base (KB) article 2571543.
You sign in to Lync 2010 by using a user account whose display name is in English.
You try to search for a user whose display name is in Korean.
You type the Korean user name in the Find a contact box, and then press Enter.
In this scenario, the user name does not appear in the search results.
To resolve this issue, install the following cumulative update:
2670326 Description of the cumulative update for Lync 2010: February 2012
To work around this issue, do not press Enter, or you can press Enter two times when you type the user name to perform the search.