Since I posted the question, I discovered how to get back to normal operation. Somehow the app got stuck on trying to stack a single image and wouldn’t allow me to just cancel the stack and return to the deep sky stacking home page. I found out I just had to proceed with stacking one image, letting the routine fail, and then the app returns to the deep sky stacking home page. Maybe an escape key stacking interrupt option is needed? Thanks for replying.
