I use to work with 2 laptops (Windows vista and Windows 7), my work files being on an external usb disk. My oldest laptop broke down, so I bought a new one. I had no option other than take Windows 8.
I suspect something changed with access rights, as my external disk suffered some "access denied" problem on Windows.
I was prompted (by Windows 8) somehow to fix the access rights, which I tried to do, getting to the properties -> security.
This process was very slow and ended up saying
disk is not ready
Additionally, my external usb disk somehow was not recognized anymore.
Back to Windows 7, I was warned that my disk needed to be verified, which I did. In this process, some files were lost (most of them I could recover from the folder found00x, but I have some backup anyway). Also, I don't know why, but under Windows 7, all the folder showed with a lock.
Then back again to Windows 8. Same problem : access denied to my disk + no way to change access rights as it gets stuck
disk is not ready".
Now I am pretty sure there is some kind of bug or inconsistency in Windows 8 / Windows 7.
I did 2. and 3. a few times. At some point, I also got an access denied in Windows 7.
I could restore access rights to the disk to "System" (properties -> security -> EDIT for full control to group "system". ).
But then I still get the same access right pb on Windows 8, and getting stuck in the process to restore full control to "system" -- and "admin" groups.
I upgraded Windows8 with the Windows8 updates available. Does not help.