When you attempt to clone or take quiesced snapshots of a virtual machine running on an ESXi 5.0 host, you encounter the following error:
Failed to start quiescing operation in the virtual machine. The error message was: (no valid message provided)
If you clone a virtual machine, or take a quiesced snapshot of a virtual machine, you are performing an I/O intensive operation. The ESXi 5.0 host might not be provisioned well enough to handle your load if I/O loads are also in the operating system.
Environment
VMware vSphere ESXi 5.0
Resolution
Configure the storage subsystem or reduce the I/O loads in the operating system until your host can handle the load. Reducing I/O loads within the OS includes, but is not limited to: stopping 3rd party tasks and perform the task during off-hours when there is less utilization.