Issue:
PowerChute Network Shutdown continually shuts down an ESXi host following UPS turn off event when A/C power has been restored and UPS turns back in an Advanced UPS Configuration.

Product Line:
PowerChute Network Shutdown (PCNS) version 3.1

Environment:
VMware ESXi versions 4.x, and 5.x
PowerChute is installed on a physical Windows machine and configured for Advanced UPS Configuration. ESXi hosts are associated with the Main Outlet Group on an Outlet Aware UPS. PowerChute is configured to turn off the UPS or Outlet group on the shutdown settings page following a UPS critical event.

Cause:
Software Issue. When there are ESXi hosts registered with the Main Outlet Group and a UPS turn off initiated event occurs PowerChute does not resolve the UPS Critical event after the UPS is turned back on.

Symptoms:
PowerChute logs the event "UPS Critical Event: UPS Turn off initiated" when a UPS turn off command is issued via the Network Management Card interface or by PowerChute in response to another UPS critical event.
The Virtual Machines and ESXi hosts are shut down.
When the UPS is turned back on and the ESXi hosts are powered on PowerChute immediately issues another shutdown command to the ESXi hosts.
PowerChute shuts down the ESXi host every time it is powered on.

Resolution:

Upgrade to PCNS version 4.x

Or
1. To prevent the ESXi hosts from being continually shut down, re-start the PowerChute Network Shutdown service using the Windows Services console.
2. To prevent the issue from occurring the ESXi hosts should be associated with a Switched Outlet Group rather than the Main Outlet Group.

NOTE:
1. Issue does not occur for Non-Outlet Aware UPS.
2. Issue does not occur for a UPS with Switched Outlet Groups only.
3. Issue does not occur when ESXi Hosts are associated with a Switched Outlet Group or if the PowerChute machine itself is shut down in response to a UPS critical event e.g. if the UPS turn off command is issued to a UPS that does not have ESXi hosts associated (Physical UPS) and the option to "Shutdown PowerChute Machine" is enabled for that UPS.
4. Issue does not occur for Single, Redundant or Parallel UPS Configurations.