Not normal .mov i.e. regular codec packs don't include it (K-Lite, CCCP, XP etc.) and VLC doesn't play it either.

I never found out the exact format, although I did not do any extensive checking. Everything I tried said either nothing at all or "Could not render file"

BTW my case was not from a Nikon camera.. can't remember the exact brand, but since this is very uncommon problem, I guessed.