>>I use Macs and can work with both D800 and D4 14-bit >NEFs >>with LR4. No problems. > >I just noticed that Apple have an OS update that adds RAW >compatibility for several new cameras, including the D4 and >the D800. I will try this when I get home. Hopefully, this >is the silver bullet.
I can now confirm this fixed my issue. The OS now reports my file sizes correctly, and LR4 is able to process my D800 NEF files without issue. I have one machine running Snow Leopard and another running Lion. Both are now updated.