Compacting a virtual hard disk can reclaim unused space in the virtual disk. Modern disks and operating systems are much more efficient at managing disk space than in the recent past. Therefore, do not expect the compacting procedure to return large amounts of disk space to the host drive.
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 Hardware tab, select the virtual hard disk, and select Compact from the Utilities menu., click the