Damn that is a long time lol
But I have seen that command in Windows do that. You will see the cpu and drive are being used, so it is working. The program simply calls DISM in windows to cleanup the competent store. I think MS has bugs in it, because when I run it for the first time on a system it only takes about 5 or 10 min. Then if I run the same command on the same system a 2nd time it takes over an hour.
Windows 8 is the first version of Windows that MS gave that command to, and looks like it still needs worked. But Dont stop it, let it finish, disable any and all programs you can to help it move along.
This is the command that is taking so long
Dism /Online /Cleanup-Image /RestoreHealth
But I have never seen it take as long as it is on your system, does the event viewer show any errors or anything?
Shane