Can you go to C:\Program Files\Epic Games\RealityCapture and use RealityCapture-1.4.0.msi to install RealityCapture. After that is it the problem still happening.
As you wrote, there are some issues with the lights, is the computer shut down during these problems?
Do you have set the autosave?
Is this also happening, when you are saving after each computation step?
Can you try also the mentioned solutions from the post attached in the previous response?