Microsoft has released a new Cumulative Update for Lync 2013 Client couple days ago. This fix addressed bunch of issues including,
Presence status isn’t updated based on Exchange calendar in Lync 2013
You can’t drag a contact from Lync 2013 to another application
Proxy authentication dialog box appears when you sign in to Lync 2013
Note that once updated, there is a known issue with this fix.
- Screen readers cannot read aloud keystrokes during a Lync 2013 application or desktop sharing session in Windows
Before applying the CU Update, Verify that below prerequisites are installed.
- MSO (KB2727096)
- MSORES (KB2817624)
- IDCRL (KB2817626)
You can download above patches and the CU update from http://support.microsoft.com/kb/2825630