Try follow this procedure:
To reset the Migrate.Enabled setting:
Connect vSphere or VMware Infrastructure Client to your vCenter Server.
Click on the ESX host.
Click the Configuration tab.
Click Advanced Settings under Software.
Select Migrate and change Migrate.Enabled to 0.
Click OK and close.
Click on Advanced Settings.
Select Migrate and change Migrate.Enabled to 1.
Click OK and then Close.