On the Exchange Team blog they recently released an annoucement, Released: Update Rollup 1 for Exchange 2010 Service Pack 2, regarding Update Rollup 1 for Exchange 2010 SP2. I wanted to call out the included note for Forefront Protection for Exchange customers who will be applying the rollup to their Exchange servers:
Note for Forefront Protection for Exchange users For those of you running Forefront Protection for Exchange, be sure you perform these important steps from the command line in the Forefront directory before and after this rollup's installation process. Without these steps, Exchange services for Information Store and Transport will not start after you apply this update. Before installing the update, disable ForeFront by using this command: fscutility /disable. After installing the update, re-enable ForeFront by running fscutility /enable.