If your ESX is managed by VC you must work with VC or disconnect ESX from VC inventory, do your conversions and connect it back.
HTH
Also it is good idea to run the GUI as administrator.
If your ESX is managed by VC you must work with VC or disconnect ESX from VC inventory, do your conversions and connect it back.
HTH
Also it is good idea to run the GUI as administrator.