To reproduce:
1. Download and extract debug_fontcrash
2. Run cmd.exe as administrator
3. In cmd navigate to the project directory
4. Type: copy dbcrlr.ttf c:\windows\fonts
5. Run the executable included in the project - it crashes
6. Open the project (or any project) with any version of Unity - it crashes
7. In the cmd, type: del c:\windows\fonts\dbcrlr.ttf

Note: it seems that executables built with Version 4.3.x don't crash, but the editor still does.