With intra-oral imaging, the more data you capture, the more processing is required, which means more time is needed to do the math. If you exceed the number of images your computer can handle, you may get an error during processing.
One thing you can do to speed things along is to crop out data that is unnecessary for the final equation. A decent computer can easily crop this out automatically during processing, but you can give it a hand by deleting unnecessary information. In this video, you can see a case where to much image capturing rendered to visualized model in the maxillary arch. We salvaged the operation by clicking RESCAN. The live images were reloaded, some extra data was cropped and processing was completed.
On a side note, the software saves these live videos on your hard-drive. Be mindful of small storage space on your C drive that can fill up real fast with saving these videos!