Hello VentureUAV,
This error shows up when RealityCapture was not closed traditionally, and there are few issues which may cause this.
It usually happens when Windows get updates, and the whole PC restarts.
The other most common cause is CPU/GPU overheating. This usually happens due to having a large number of images, or if RealityCapture is not able to align images (due to images that create a component with geometry issues), or a component with geometry issues was created and RealityCapture is not able to create a model from that component.