--- Operating System, Graphics card ---
Arch Linux (x86-64), Kernel: 3.11.6-1
nVidia Geforce GTX 670

--- Blender version with error, and version that worked ---
2.69, 2.69-r61076

--- Short description of error ---
The mesh for modification(MeshDeform) of the mesh object which is having Vertex Group referred and using Mirror Modifier cannot be edited.
Because, blender will crash if try to go into Edit Mode.


--- Steps for others to reproduce the error (preferably based on attached .blend file) ---
Open attached file. try to edit the mesh of Cube.001.