Came across this amazingly obtuse error today trying to deploy a new VM
Module ‘MonitorLoop’ power on failed
And was unable to power on the vm. I was surprised to find that despite the data store having some free space, this error actually indicates there is not enough space to inflate the Swap file (being 0k when powered off, and it can’t then extend to the correct size).
You can see this by going to the details of the task and digging into the error stack.
Move the VM to a data store with more space, or increase the free space on the data store and the VM will successfully power on.