VPC allows you to "reclaim unused disk space" using the Virtual Disk Assistant. However, unless the unused disk space has been zeroed, it cannot be reclaimed. In the past, I had been using a variety of Windows disk utilities to zero the unused disk space. Users of VPC know that everything takes a long time in VPC, including zeroing the free space. Today, I discovered a much quicker solution.
WARNING: Before you try this, do yourself a huge favor and back up the VPC files that you are going to work with. Don't assume that it will always work as well as it did for me.
Here's what I did:
- Launch the PC and defragment the drive.
- Shut down the PC.
- Control-click on a .vpc7 document and choose the Show Package Contents option.
- Double-click on the BaseDrive.vhdp file (this will mount the disk).
- Open Apple's Disk Utility program.
- Select "No Name" -- under BaseDrive.vhdp.
- Click the Erase tab.
- Click Erase Free Space.
- Select Zero Out Deleted Files and click Erase Free Space.
- Use VPC's Reclaim Unused Disk Space tool.
The Results:
- File size before normal Reclaim Unused Disk Space: 7.53 GB
- File size after normal Reclaim Unused Disk Space: 6.17 GB
- File size after using this hint: 4.86 GB

