If you start, stop, restart, or migrate a virtual machine, you must close the virtual machine console and then re-open it from the Oracle VM Manager Web Interface. If the virtual machine console is open during the migration of a virtual machine or when a virtual machine restarts, the console becomes unresponsive and no longer displays output for running processes.
Workaround: Close the virtual machine console and then re-open it from the Oracle VM Manager Web Interface.
Bug 22735310 and 22779973