Corrupted Virtual Disk Image

Hi,

I am using Mac OSX 10.7.5 on a MacPro (12 cores, 32 GB ram) and I created a very large virtual disk.  Around 100 GBytes.  I'm using PGP Desktop version 10.2.1

After a few days I rebooted and the file size of the virtual disk shrank to about 64 MBytes.  And of course, it won't mount. 

Any ideas as to what happened?  Is there a way I can fix this virtual disk and get our stuff back?

Thanks

Kevin