У нас была та же песня вот что наш человек нашел и прислал всей группе, как бороться...
It turns out the VPC’s can dynamically grow but have no mechanism for dynamically shrinking, which explains why some of the VPC images are over 6 GB. The process involved for managing VPC’s if they get out of control is as follows.

1. Download Eraser, (http://www.tolvanen.com/eraser/) and install it in the guest OS. This utility was recommended by Microsoft so we can only assume it’s the best available (J).
2. Defragment the guest OS hard drive.
3. Backup any critical data in the guest OS.
4. Run Eraser in the guest OS.
5. Click Edit, then Preferences, then Erasing
6. Select Unused Disk Space
7. Select New
8. Enter the description Blank
9. Click Add
10. Create a 3-byte pattern of zeros
11. Click Save
12. Select Blank under Unused disk space
13. Click OK.
14. Click File, then New Task
15. Select Unused space on drive
16. Select Local Hard Drives
17. Click OK
18. Select Task, then Run on the previously created task
19. Wait for completion
20. Close the report
21. Exit Eraser and shutdown the guest PC.
22. Use Virtual Disk Wizard on the Host PC to reclaim lost space. Click File, then Virtual Disk Wizard.
23. Click Next to start the wizard.
24. Select Examine or modify existing disk and click Next.
25. Click Browse to locate the disk image, double-click the image file and click Next to continue.
26. Select Compact the Disk image and click Next.
27. Select New File, browse or enter a new location and filename, click Next to continue.
28. Click Finish to start the process.
When finished, click Close.

I tried it out and it works great. I had a VPC that was pushing 7 GB and after following these steps I had it down to 2.8 GB

Удачи!