Lync Contact Cleaner
The Lync Contact Cleaner provides you with a way to quickly and easily scan your contact list for non-functional contacts whose presence no longer shows up (ie. dislplays “Presence Unknown”).
You then have the option to remove contacts one by one, select multiple, or all of them.
This can be especially useful if you use Lync Online (part of Office 365) where contact lists are limited to 250 individuals.
Available as a free download from the Microsoft TechNet Gallery.
Supports both Lync 2010 and 2013.
NOTE: Some contacts may show up as being non-functional but in actual fact still may be – the remote Lync Server has simply not displayed their presence in time. Be careful in your choices of which contacts to remove.