Article ID: 2800073
When using System Center 2012 Virtual Machine Manager SP1 to put a cluster node into Maintenance Mode by right-clicking on the host and selecting "Start Maintenance Mode", manual or system refreshes of the cluster fail with one of the following errors/warnings while the "Start Maintenance Mode" job is still running:
Host cluster <name> was not fully refreshed because not all of the nodes could be contacted. Highly available storage and virtual network information reported for this cluster might be inaccurate.
Ensure that all the nodes are online and do not have Not Responding status in Virtual Machine Manager. Then refresh the host cluster again.
Unable to perform the job because one or more of the selected objects are locked by another job.
The "Start Maintenance Mode" process locks the host that is being put into the Maintenance Mode, the cluster where the host is located, and all the virtual machines on the host. These objects remain locked while the "Start Maintenance Mode" job is running. Since these objects are locked, manual or system refreshes fail while the job is running.
This behavior is by design. Once the "Start Maintenance Mode" job is complete, both manual and the system refreshes of the cluster should complete successfully.
(http://go.microsoft.com/fwlink/?LinkId=151500)for other considerations.