Strange 'Result too large' error when copying

[dnanian]

Well, I was wondering if the disk -- at the time you got that error -- had enough space on it. I'm guessing it was actually full.

There's a bug in a low-level Apple routine we use where, if certain files are written to at the same moment we're copying it -- typically over and over -- it'll look larger than it really is, and get copied until the disk is full. This happens at a point where we don't have control, and while we've reported it to Apple, it's hard to work around... but we're trying...