Exchange 2010 Databases dismounted and won't mount.
We have a cluster with 2 Virtual exchange servers that early this monday morning had all databases dismounted.
When trying to mount the drives we would get an error.
Come to find out the virtual machines get auto updates and after a list of patches for .netframework 4 the VMs rebooted(1 last thurday and 1 late sunday evening) When these machines rebooted the Cluster service failed to automatically start. Once started the issue was resolved.
The Custer Service needed to be restarted.