Recently during a Veeam backup HA kicked in due to a problem with VCenter and marked two machines as Invalid

•  Veeam started backup and created snapshot on affected VMs
• HA kicked in after VCenter Server failure
• Vcenter tried to move the machines after the HA event but they were locked by the snapshot Veeam had (the hypervisor has a lock because of the snapshot)
• Machine couldn’t move but Vmware removed them from inventory and tried to register them to another host, without success
• Machines marked as Invalid, Removing machines from Inventory and registering the machines manually did not work
• The machines are locked however still powered on and response

Fix to get VM’s registered on VCenter

• Stop any tasks (i.e. Veeam) that might trigger a snapshot on affected machines
• Temporarily disable DRS in the cluster (when we power up the machine we don’t want Vsphere to power it up on another host otherwise the lock will persists)
• Power affected VMs off gracefully from within the OS.
• Login to vcenter and select Host which failed and . Unregister “unkown” VM’s listed (these should be the actual Vms). Unregistering should remove the lock.
• Register the virtual machines using the vmx files in the datastore
• Check no snapshots are present, if yes delete or consolidate
• Power on Vm
• Re-enable DRS