When I select “Clean up Disks…” for my vm, it says “Reclaimable space: 150GB”. I click “Clean up now”, it does its thing, and it says it succeeds in doing that. No error message. But when I go back to clean up the disk again, that 150GB is still there. I never get back that 150GB on my hard drive. Why is this, and how can I fix it?