During installation of Exchange rollup update for Exchange Server 2007 and Exchange Server 2010, some Exchange services e.g. Microsoft Exchange Transport Service may fail to start. This issue occurs because there's a problem the way Exchange services interact with Forefront during patching process. A suggested workaround is to use a Windows PowerShell script to disable and enable Forefront Service for Exchange during installation.
A new feature was introduced in Exchange Server 2007 SP2 to allow admin run PowerShell scripts during rollup installation. For more information, please refer to .
"The script in this article demonstrates how to use CustomPatchInstallerActions.ps1 file to disable and enable Forefront service for Exchange utilizing this new feature. However the script can be customized by customers for use with other third party products in this way."