Like others have said, shut the nano down or wait till it is complete finished before starting or resuming the render. Not sure what your system specs are, I've had renders take up to 5 min to stop, and over an hour for the render line to appear when resuming. I have a 1GHZ P111, the image I've been rendering ( high setting ) has gone at times for 8 hr. and not even reports 1 %. Anyway what might help you get through some tough renders is, Go to Edit/Preferences make sure... Image with scene Open/Save... is enabled. Render the scene, after awhile while the render still looks like it's going fine, stop it and save, then continue by using the resume render button, do this in increments of 8 hrs or whatever. If it seems like the render has froze try stopping it. Give it plenty of time, if it still appears froze shut the program down manually, and reboot. When you open the file back up you should be able to resume the render from the last save. It's very important that you do not open the bmp ( image ) being saved with the project file, if you open it while the render is running it will probably freeze the render and corrupted the bmp for the open/save option ( the render will have to be started over instead of resumed ) It's also very possible it will corrupt the open/save option if you open the bmp even when Bryce is shut down and not using it.

Stephen Ray