Update Rollup 3 for Exchange Server 2007 SP1 and Update Rollup 7 for Exchange 2007 RTM can cause issues
During some searching on the forums, I read a lot of messages about problems after installing the last rollup packs for Exchange. Rollup pack 3 for Exchange 2007 SP1 as wel as rollup pack 7 for Exchange 2007 RTM can cause problems. Microsoft has admitted that there are issues with it and has released some solutions to solve this issues. Have a look at the following site to find out how to solve it.