Assumes you are in Monitor Mode.
Select menu item Monitor, Enable Capture to File. So that there is not check mark beside item, to stop capturing video motion.
Select menu item Monitor, Monitor Stop.
Result:
Stopped capturing video to file and the video file is now saved.
Right half of screen should be blank white, and your back to just Video Mode.
Note:
When exiting Monitor Mode or Web Mode, video is saved to file and a new video
file is created. Toggling, Enable Capture To File, starts and stops capturing
motion video to the same file - it does not create a new file.