Microsoft has released Update Rollup 1 For Exchange 2007 SP3. For a list of changes that are included in this update rollup, see KB2279665.
- Exchange 2007 SP3 must be installed prior to installing this update rollup.
- This update rollup cannot be installed if you are using Exchange 2007 RTM, 2007 SP1 or 2007 SP2.
- Any interim Updates (from Microsoft PSS) for Exchange 2007 must be uninstalled prior to installing this update rollup.
- To remove Update Rollup 1 for Exchange 2007 SP3, use Add/Remove Programs in control panel and remove update 2279665.
- Forefront users have to disable it fully before installing the rollup and enable it afterwards by running the commands from the forefront directory.
- Before installing the rollup, disable ForeFront by running the "fscutility /disable" command.
- After rollup installation completes, re-enable ForeFront by running the "fscutility /enable" command.
Download the rollup from here