Assume that you sign in to version 14.0.5 of the Microsoft Lync for Mac 2011 client. When you try to click the Phone tab, the user interface freezes. However, the menu bar is available.
This issue occurs because the NSConcreteMutableAttributedString function cannot paint the user interface when there is data that is not parsed to a valid telephone number.
To resolve this issue, install the following cumulative update:
2888920 Description of the Microsoft Lync for Mac 2011 14.0.6 update