Nonadministrative users in the guest operating system are able to shrink virtual disks. Shrinking a virtual disk reclaims the disk's unused space. However, if you shrink a disk repeatedly, the disk can become unavailable or cause a Denial of Service (DoS). To prevent this, disable the ability to shrink virtual disks.


Turn off the virtual machine.


  1. Log in to the vCenter Server system using the vSphere Client.
  2. Select the virtual machine in the inventory.
  3. On the Summary tab, click Edit Settings.
  4. Select Options > Advanced > General and click Configuration Parameters.
  5. Add or edit the following parameters.
    Name Value TRUE TRUE
  6. Click OK to close the Configuration Parameters dialog box, and click OK again to close the Virtual Machine Properties dialog box.


When you disable this feature, you cannot shrink virtual machine disks when a datastore runs out of space.