I’m running the standard 2.47 Win32 release.
I’m not sure if this is a bug or just something I’m not supposed to so (mathematically speaking).
Please test by opening this .blend then try to click the up arrow to Move the Subsurf Modifier up in stack. This is causing Blender to quit every time I try it.
To test it manually:
add cylinder 8 faces (or more)
edit CTRL+R to add split faces into 3 sections (or more)
extrude selected faces
add edgeplit modifier: split angle 0 (unclick Marked as Sharp)
add subsurf modifier: levels/render levels 4
Click up arrow on Subsuf to move modifier up in stack
edge-sub-crash.blend (38.7 KB)