Is it possible to convert Thick VM to Thin after creation in vSphere 5.1? I know Motion can do it, but can it be done directly in vSphere, or must it only be done from initial creation?
One option is to use the vmkfstools command line utility to clone the virtual disk.
vmkfstools -i source.vmdk target.vmdk -d thin
Please be careful with this command, if the VM has active snapshots!