There have been several reports of BCS closing after running a few minutes. The memory usage in the task manager will steadily climb while BCS is in edit or simulation mode tell it reaches a limit and then the program will close. The cause is a bug in the video drivers for some ATI cards. Please update your video drivers to the latest from http://www.ati.com if you are having this problem.
Here is a list of confirmed cards and driver versions with the problem:
ATI Radeon HD 3300 Series
Driver Version: 8.671.0.0
ATI Radeon HD 5800 Series
Driver Version: 8.671.0.0
ATI 3400
9.11 Catalyst drivers.
Driver Version: 8.671.0.0
ATI Mobility FireGL 5700
driver version 8.641.1.1000
ATI Radeon HD 2600
CatalystT Version 09.8
Driver Packaging Version 8.64-090714a1-086704E-VisionTek
Another problem card and driver version:
ATI Radeon HD 4800 Series
Driver Version: 8.690.0.0
Another one:
ATI Radeon Mobility HD 5650
driver version 8.692.1.0
HD Radeon Mobility 4670 with 8.692.1.0