I've had this issue for a little while but did nothing about it.
I have a caddy in my PC and I removed my HDD from it many times and it has worked fine. Now it's in there and I had to to a "check for consistency" before Windows loaded. I could have skipped the check but I did not notice in time. It started doing the check and I let it, but it was taking far to long and I had to get on so I reset my PC then the check came up again and I skipped it.
Now the HDD only shows about 640gb is used but when I select everything in it's 580gb. That extra space is all my music and a few games, which I don't want to lose.
So I have no idea where it could have gone, any ideas? I ran the consistency test again but that didn't help.