If your virtual machine has several snapshots, and you want to delete all except the last one, Parallels Image Tool provides the simplest way to merge them.
To merge snapshots of a virtual machine:
/<Username>/Documents/Parallels/
folder in Mac OS X.
C:\Documents and Settings\<Username>\My Documents\Parallels\
folder in the Windows primary OS.
/<username>/parallels
directory in the Linux primary OS.
Note: The virtual machine using this virtual hard disk should be stopped before proceeding.
The information from all the snapshots will be merged to the last one, and all the other snapshots will be deleted. Parallels Image Tool does not change the snapshots tree in Snapshot Manager, so if you attempt to revert to any snapshot of the tree, it will be no longer accessible, and you can remove it manually.