[Trick that actually works] If you have an iPhone capable of shooting ProRes video, go into your camera, go into video mode, and enable ProRes. You’ll notice a ticker at the top that tells you the maximum amount of time you can shoot in this mode. It will more than likely be 0 minutes, but you will see right below that a spinning ticker saying “optimizing resources.” This is getting rid of that system data that’s unneeded. I just left my phone in this mode for a few minutes and it freed up five minutes worth of video, but then gave me the option to continue free resources. It essentially got rid of the rest of the system data that wasn’t needed and left me with the free space above!