- VM you want to convert is powered down.
- SSH into the host.
- cd /vmfs/volumes/DatastoreName/virtualtoconvert
- change thick to thin volume whit this command vmkfstools -i old.vmdk -d thin new.vmdk
- remove old disk from VM without delete from datastore
- Unregister VM from ESXi inventory(Right-click VM > Unregister)
- Re-register the VM (Create / Register VM > Register an existing virtual machine)
- Add new Disk to VM
- Boot the VM and check all is well.
- Delete old vmdk and flat.vmdk files – rm old.vmdk && rm old-flat.vmdk
