While using your virtual machine the virtual hard disk has been enlarged and now occupies too much disk space on Mac HD. You wish to reclaim the part of unused hard disk space from the virtual machine back to Mac.
In Parallels Desktop 10 we introduce a Free Disk Space Wizard for managing your virtual machines data usage: just go to File -> Free Up Disk Space (when Parallels Desktop is in front):
For more information about Snapshots please visit Working with snapshots
In Parallels Desktop 10 we introduced new Real-time Virtual Disk Optimization feature, which is designed to compact a virtual hard drive automatically, in the background, while virtual machine is running. For more information about Real-time Virtual Disk Optimization please visit KB122668