I got two opened without breaking the clips. If you start at the bottom or top between the outer shell and inner case that holds the drive with a small flat screwdriver then wedge in that opening a flat piece of plastic like what in this kit
Amazon.com: JC Performance Plastic Interior Wedge Tool - Automotive Trim tool (5 Piece, Blue): Automotive
Get one wedge in place then do the opposite side using the same method, when both the top and bottom are wedge in place then apply pressure to each to slide the case out of the shell. The two I did popped right out withoutbreaking the clips.
I don't know if you're talking about this specific case, or a previous version of a WD My Book, but in this case, the "clips" are not on the top or bottom edge at all. There are guides that slide on a rail, but you don't want to pry on those at all. The clips are actually on the back edge, on the side where the USB and power plug are at. The video above shows how. There's no "prying" - that's a sure way to risk breaking something. When you slide the cards in, what you're really doing is pushing a retention notch out of the notch in the outer casing, which releases and allows you to pull the inner case out. There's no "prying" at all, just "sliding".... this is by the way, different than previous generation My Books which I've opened too.
This was my first time opening this new style My Book, and with that video, it was quick and simple and no stress on the plastics at all. Once you get it, this style is actually a lot easier to open than previous versions.