Your network has Lync Server 2010 deployed.
Several users report that they are unable to add more contacts to their Contacts lists.
You need to verify whether the users’ Contacts lists reached their limit.
What should you do?

A.
At the command prompt, run cserror.exe.

B.
At the command prompt, run dbanalyze.exe.

C.
From the Lync Server Management Shell, run the Get-CsUser cmdlet.

D.
From the Lync Server Management Shell, run the Get-CsUserDatabaseState cmdlet.

Explanation:
http://blogs.technet.com/b/csps/archive/2010/06/06/howtolimitcontacts.aspx