I installed the Kangaroo plugin and tried to open this gh definition KangarooCPmultiradii.gh (14.5 KB) (its a fixed radius circle packing algorithm). I got an error message warning me of 4 IO Grasshopper errors. I dismissed the message and rhino WIP crashed. I had a similar errors with another definition by David Picker found here http://www.grasshopper3d.com/group/kangaroo/forum/topics/circle-packing-definition but no crash.
Here is the crash report sent to apple: GfM_Kangaroo.txt (94.5 KB)