After upgrade from Pycharm 2017.2.3 to Pycharm 2017.1.4 Pycharm\'s Debugger suggested to build cpython (or sth associated with it):
Pycharm 2017.2.3
Pycharm 2017.1.4
p
Try clearing all your breakpoints. Worked for me. Also check you have no problem when doing Run instead of Debug.