

To remove all Lync files from your computer, delete the following folders in the Users/username/Documents/Microsoft User Data folder: Users/username/Library/Logs/Microsoft-Lync.log Note This file is present only if you turned on Lync Logging. Users/username/Library/Logs/Microsoft-Lync-x.log Users/username/Library/Preferences/ByHost/ To remove your existing Lync preferences, delete the following files: Log on to your computer by using administrative credentials. If the issue is resolved by creating the new profile, it will be determined that the issue was caused by a corrupted profile. If you contact Microsoft technical support, you may be asked to create the new profile as a troubleshooting step.

You may be able to avoid uninstalling Lync for Mac 2011 if you create a new profile on the Mac.
