Compacting a virtual hard disk reclaims unused space in the disk. If a disk has empty space, this process reduces the amount of space the virtual hard disk occupies on the host drive. You must power off a virtual machine before you compact its virtual hard disk.

You cannot compact a virtual hard disk if disk space is preallocated or if the virtual hard disk is mapped or mounted.

To compact a virtual hard disk for a selected virtual machine, select Virtual Machine > Virtual Machine Settings, click the Hardware tab, select the virtual hard disk, and select Compact from the Utilities menu.