My simple photo rendering is stopping in between without showing any progress. and when i stop the rendering then save button is not visible at this time (When it is stuck).

i am using mac 10.12 , simple photo rendering 2.4.1 .

after in progressed for couple of hours then it stuck then there is no way to retrieve photo it created. need help in fixing this issue . At least can you please let me know how to retrieve photo it created till that point.

Below are setting i am using.

1) depth of field and best quality with sky light on.
2) below are advanced settings

AA_minsamples 16
lighting method sppm
normallens.radios 0.1
remaining all default settings.