I was one of the unfortunate admins who chose to perform routine server maintenance on our Exchange server on a day when Microsoft accidentally released a pre-release rollup 4 package via Windows Update. I currently have exchange version 8.1.311.1, which is Exchange 2007 SP1 with Rollup 4. We have a few Symantec Backup Exec 12 problems which I have read are caused by this rollup. See here: http://msexchangeteam.com/archive/2008/09/11/449787.aspx
My question is can I install the Rollup 4 version 2 over top of rollup 4 version 1? Or should I uninstall the version 1 rollup and then install the version 2 rollup.