Cannot Install OCS 2007 R2 After Installing Lync 2010

The importance of schema prep order

Today I re-learned the importance of running the Schema preparation steps in order. Like most geeks, I like playing with technology. And, in many cases, that includes finding its limits and where it breaks.

In reviewing the list of schema additions added by Lync Server 2010 and comparing them to the additions by OCS 2007 R2 it appeared that Lync's additions were a superset of OCS. I have a few live Lync lab environments right now so decided I'd try an experiment in one. I thought I'd try to add an OCS server after the fact. In other words, I'd built up a virgin domain, then run the Lync preparation steps then installed my Lync environment. And now I wanted to add an OCS server.

This isn't entirely unreasonable as I expect some customized integrations and third party applications that work fine with OCS won't work at all with Lync. UCMA has changed significantly and that may cause some backward compatibility issues.

My journey ended pretty quickly however in that the OCS installation wizard said the preparation steps were only partially completed. Since I didn't care what I broke, I decided to run the OCS prep steps. They failed miserably. And that's probably a good thing since it likely would have broken everything Lync-related.

This behavior isn't entirely unexpected since the same thing happens with Exchange 2010 and previous versions. That said, I wanted to test it to make sure. The easy solution here is that if you think you'll ever want an OCS server in the environment, run the OCS prep steps first and install at least one server before running the Lync AD preparation steps.

• Microsoft
• VoIP / Convergence
• CS2010
• Lync
• MCS2010
• Microsoft
• OCS
• Office Communications Server 2007 R2
• VoIP