Boot Camp Assistant crashes when partitioning drive (exception: EXC_BAD_ACCESS)
Run Repair Disk on your boot partition. To accomplish this, reboot your Mac into the recovery partition, holding down ⌘R when you see the Apple logo. Select Disk Utility from the menu, then in the First Aid tab click Repair Disk. This may take some time. Partitioning trouble is usually a file system or disk hardware problem; this will solve the former, and a trip to the Apple store is usually needed to address the latter.