VMware handing out duplicate MAC addresses causing VMs to go in Power Off state.
The following error can be found in VMware when trying to close the VM impacted.
VC MAC address space is exhausted
Based on VMware KB 1024025, this issue is due to the fact that two or more vCenter Server instance ID are identical.
This causes the MAC address from generated VMs to have very similar MAC address which can overlap overtime.
If this doesn't fix the issue, please contact your vWorkspace support