VM Configuration File Missing Alarms is an event-based vSphere alarm happens when VmConfigMissingEvent is triggered.
The event is created when the configuration file cannot be found.
You may have storage or permissions issues.
Could you specify if it happens with one VM or several VMs, are they on the same datastore? Does the alarm appear when you power VM off or when you reboot them?
There is also a similar question
on a VMware Community Forum.