If the path to FreeCAD.app (MacOS application bundle for FreeCAD), or just the FreeCAD binary, contains unicode characters outside of the ASCII range then it won't launch properly. I suspect this comes from the app initialisation python script ( src/App/FreeCADInit.py ), which means that it likely occurs on other platforms than MacOS as well.
Steps To Reproduce
1) Make directory named uñîcøde
2) Copy FreeCAD.app in to it
3) Try to launch FreeCAD.app
Observe popup containing text like:
While initializing FreeCAD the following exception occurred: ''ascii' codec can't encode character u'\u0303' in position 23: ordinal not in range(128)'
Python is searching for its files in the following directories:
Python version information:
2.7.13 (default, Dec 18 2016, 07:03:34)
[GCC 4.2.1 Compatible Apple LLVM 7.0.2 (clang-700.1.81)]