Assume that a version 14.0.7 of Microsoft Lync for Mac 2011 is running on a device. Then, you plug in or unplug a USB headset or an external monitor from the device. In this situation, Lync for Mac 2011 may crash.
To resolve this issue, install the following hotfix:
2926055 Description of the Microsoft Lync for Mac 2011 14.0.7 hotfix