I Have run into this problem 2-3 times last week, so I wanted to remind people about the issue.
The error you see is that your Lync or OCS Front End service centers will not start and errors a la the following is logged in your event viewer:
The evaluation period for Microsoft Office Communications Server 2007 R2 has expired. Please upgrade from evaluation version to the full released version of the product.
Failed to activate Office Communications Server Standard Edition Server on machine R2 SE.NWTraders.com
Or in Lync
The evaluation period for Microsoft Lync Server 2010 has expired. Please upgrade from evaluation version to fully licensed version of the product.
There are 2 possible sources of error for this:
You (or the colleague who usually gets the blame) made a mistake
It installed the eval version of Lync and the 180 days are now gone, so the product has expired
Find the full version of Lync, copy it locally into the server and run:
msiexec.exe / fvomus server.msi EVALTOFULL = 1 / qb
If it comes back with a message that it can not upgrade FULL to FULL, then the next source of error is:
Microsoft made a mistake
Or rather they have addressed a critical issue in their CryptoAPI (and we're happy for that), but this correction criples OCS and Lync (and LCS for that matter), so the product think it is running on an evaluation version. The error is described here:
and solved by setting a registry setting or running OCSASNfix.exe from a command prompt.
Good luck out there!