OS X 10.8.5 (12F45)
NVIDIA GeForce GT 650M 1024 MB
Broken: 2.73.8 (cdc1dab)
Worked: official 2.73a (bbf09d9)
Short description of error
When I try to create a directory in the file browser by typing the name in the file path, I get the pop up "OK? Create New Directory". So far so good. But when I click on the popup Blender crashes (the directory gets created though).
If I use the button "Create New Directory" it works fine.
Exact steps for others to reproduce the error
Open Blender. Go to the file browser (open file, save, save as..., it shouldn't matter). Click on the file path (directory) entry and type a new name at the end, press Enter. The popup should appear and when you click on it, Blender crashes.