Probably you have noticed that installing Rollup Updates for Exchange Server 2010 can take a considerable amount of time. Most of this time is spent when Native Image Generator (NGEN) is creating native images for Exchange Assemblies. While this process is taking place, Exchange services are stopped and disabled, and correspondingly – Exchange server is not available.
Taking a closer look reveals that a huge number of connections to Microsoft’s Certificate Revocation Server are being established in the background. As a result, the installation of the Rollup Updates slows down. Surprisingly, the reason for this behavior is Internet Explorer, and more precisely, one of its advanced settings – Check for Publisher’s Certificate Revocation.
As you will see in the following Screencast, disabling the option Check for Publisher’s Certificate Revocation in IE significantly reduces Rollup Updates installation time/Exchange downtime.