I use to work with 2 laptops (vista and win7), my work being files on an external usb disk. My oldest laptop broke down, so I bought a new one.
I had no option other than take win8.

1/ I suspect something changed with access rights, as my external disk suffered some "access denied" problem on win8.
I was prompted (by win8) 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".
Additonnally, the usb somehow was not recognized anymore.

2/ Back to win7, 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 win7, all the folder showed with a lock.

3/ Then back again to win8. 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 inconsistence in win8 / win7.

I did 2/ and 3/ a few times. At some point, I also got an access denied in win7.
I could restore access rigths 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 win8, and getting stuck in the process to restore full control to "system" -- and "admin" groups. Now, after I tried for more than 3 days, I am losing my patience with that bloody win8 which I did not want to buy but had no choice.
I upgraded win8 with the windows updates available. Does not help.

Anybody can help me ?