When installing a Exchange 2007 SP1 in Cluster Continuous Replication (CCR) cluster, the passive node installation fails with the following error:

“This is not a passive node. A clustered mailbox server represented by the cluster resource group [name of cluster] was found on this node.”

After a bit of head scratching, I realised that this occurs because after the installation of the passive node, Exchange setup asks you to restart your server thus causing the cluster to fail over.

The solution: well.. simply restart the passive node and run Exchange setup again.