atkpython.exe Stopped Working

There could be several reasons for this. First open the output file and check for more detailed error messages. If you are using ATK 2015 the error can be caused by a license error. The error message will be printed in the log file. If you are attempting to run a DFT or a Semi-empirical calculation and get the following error:

 License Error: (Internal: 147 Feature: ATKMaster)
 [LOCAL] C:\Users\user\.quantumwise\licenses\license.lic - (Err: 9) Feature not found
 License configuration (environment variables):
 QUANTUM_LICENSE_PATH = 'C:\\Users\\user\\.quantumwise\\licenses\\license.lic'

it means that this feature is missing from your license file. A common reason is that you are trying to run the DFT calculation with the free VNL license for academics. Notice that the ATK-DFT and the ATK-SE packages are not included in the free VNL license for academics. For that you will need to purchase a license since ATK licenses are not free, only VNL is (for academics). Of course, you can apply for a trial license so you can test these software features for your research.