I had the same problem which was fixed by turning off my UAC. To do this you:
1. Click the Start Menu.
2. Click on Control Panel.
3. Scroll down to User Accounts and click on it.
4. Now click Change User Account Control settings.
5. Scroll the slider down to "Never Notify Me When".
Now you...
Hey, I made an account just to post this :P
This tutorial has made me a very happy man. My 20gb hdd just wasn't cutting it anymore. Now I re-downloaded all of my dlc as well as installing a few games and I have 198gb left.
One thing to note is that the tutorial worked 100% for me until I...