Information
Disable virtual disk shrinking.
Shrinking a virtual disk reclaims unused space in it. The shrinking process itself, which takes place on the host, reduces the size of the disk's files by the amount of disk space reclaimed in the wipe process. If there is empty space in the disk, this process reduces the amount of space the virtual disk occupies on the host drive. Normal users and processes-that is, users and processes without root or administrator privileges-within virtual machines have the capability to invoke this procedure. A non-root user cannot wipe the parts of the virtual disk that require root-level permissions. However, if this is done repeatedly, the virtual disk can become unavailable while this shrinking is being performed, effectively causing a denial of service. In most datacenter environments, disk shrinking is not done, so you should disable this feature. Repeated disk shrinking can make a virtual disk unavailable. Limited capability is available to non-administrative users in the guest.
http://pubs.vmware.com/vsphere-65/topic/com.vmware.vsphere.security.doc/GUID-9610FE65-3A78-4982-8C28-5B34FEB264B6.html
Solution
# Add the setting to all VMs -
Get-VM | New-AdvancedSetting -Name "isolation.tools.diskShrink.disable" -value $true