System Information
OS X 10.9.1. Nvidia GForce GT 750M/Intel Iris Pro. (whichever one is in effect at the time...)
Blender Version
Broken: 2.69 (Hash: f469cbe)
Worked: 2.68.5
Short description of error
See title. Not much else to add. Crash every time with rigged mesh. No crash when exporting with 'Export for OpenSim' unchecked, or when exporting non-rigged mesh.
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps
Open attached file on a Mac - OS X 10.9.1
Export with option mentioned checked.
Crash report here: