In some cases, in VMWare Vsphere environment, SAN or NFS datastore suddenly failed. After the datastore restored, some VMs located on the datastore might be inaccessible mode and the VM icon is grayed out.
When you login into VCenter or ESX host, you can see that some VMs are grayed out, like the red labeled square in following screenshot:
1. Login into ESX host via ssh client.
2. Run command:
3. Check the output “Skipping invalid VM” message. Each line of this kind of message means one inaccessible VM. Remember their ID. In this example, there are 5 inaccessible VMs and the IDs are 1/4/6/11/12.
4. Run the following command to reload one VM:
vim-cmd vmsvc/reload 1
5. After reload command, run getallvms again to check it. This time you can see that VM id 1 is not invalid and it’s available now.
6. Go back to step 4 to reload all other inaccessible VMs.
This is a known issue of ESX5’s inventory. You can reload the VM and make it usable.
For production environment, it's highly suggested that there should be duplicated paths to your storage. This can help you a lot while one path is failed.