There are early indications that some new XBox One consoles have bad Bluray drives. The problem is immediately obvious: the drive can't read discs, and may produce abnormal knocking sounds.
Microsoft says that the problem is "affecting a very small number of Xbox One customers". Sound familiar? That's what Microsoft said about the classic "Red Ring Of Death" problem on the XBox 360. That problem led to at least one set of design changes for the 360.
Microsoft also says: "We're working directly with those affected to get a replacement console to them as soon as possible through our advance exchange program." So if you experience this problem, contact Microsoft support to get a replacement.
UPDATE: Apparently Microsoft is giving away free games to XBox One owners affected by this problem, and at least one person was able to fix their console through application of "percussive maintenance".