Some customers have reported problems downloading updates for the antivirus engine after installing the Forefront Server Security Management Console (FSSMC) Hotfix Rollup 5 and the Forefront Security for Exchange Server (FSE) Service Pack 2 Rollup 2.
The basic symptom is that antivirus engine updates fail. If you are experiencing this problem, please refer to the Microsoft support KB article #2410444 for information on how to resolve the problem. The KB will guide you through steps that will enable FSE to use the previous version of the antivirus engine and updates until a permanent fix is created.
If you continue having problems after trying the measures in the KB article, you should contact CSS for additional help.