When an engine is taken offline during the cleanup process of a scan engine update, a time out may occur. When this occurs, the GetEngineFiles.exe process incorrectly deletes some files on a computer that is running Microsoft Forefront Security for Exchange Server. Some files are deleted from the root drive instead of from the engine directory itself.
To resolve this issue, install Forefront Security for Exchange Server with Service Pack 2 (SP2).
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
Description of Forefront Security for Exchange Server with Service Pack 2