Out of nowhere, the Unauthorized Change Prevention Service in Trend Micro Worry Free Business Security 5.1 would no longer auto start on SBS 2003. We tried restarting the service manually, but no luck.
We contacted Trend, and they recommended we download and install patch 1 to resolve the issue. However, that did not work, so they asked us to remove and reinstall the client portion, ensuring it was completely gone per this KB. Once that was done, that did the trick.