The system was power off automatically from time to time. The VMware OS was power off the system automatically in order to power save. To fix this issue you have to update the BIOS version (or to set-up to disable the C-state, EIST and ACPI). After update the customer was receive a memory alert in vcenter, but without any description.
This is a false alarm, , if there is some log in hardware about memory , it is possible that vmware will report memory warning and memory alert messages.
In order to solve this issue you have to update the VMware. Please read release note:
In vmware 5.5, this issue is resolved in update 2. We can find the release notes here :
And in vmware 5.1, it is fixed in KB 2070667, the PR1145533 is about this issue.: