Virtual Machine have red alerts but there are no alarms triggered

With a college of mine, I’m setting up a new business. Where going to provide a virtual desktop to (small) customers who have the need for a enterprise enviroment (mail, shared calanders, shared storage etc) but don’t have the budget for it. When we combine all those customers together you have a budget to provide those functionality at a fractions of the costs.

Of course we want to use VMware vSphere and View for this environment. Later I will provide some more details.

First step was to setup a test enviroment so we can show some functionality to customers. All went fine until my lab had a power failure. And of course at home I don’t have a UPS who can back this up. I switched on the power again and my servers start up up (very loud,because in my lab I only have one power supply connected.)
When I opened vCenter again I noticed that some virtual machine have red alarm icons on them. But when I looked at the alarm tap there was no triggered alarm.

So what trigger this red alarm icon. After some investigation I discovered that the ESXi servers where up and running before the storage was available. When the datastores where available the virtual machines where started. But the weren’t properly registered. A simply vMotion to another ESXi host solved the problem.