If you are an Amazon fire stick user, always try using the compatible cables and storage devices. If you do not use the compatible ones or do not fix the cables properly, you will end up getting the Firestick optimizing system storage and applications error on your display screen.
You can try unplugging the cables and connect it back once again.
If the errors still persist or if your fire stick gets stuck on the optimizing screen, try to contact our Amazon fire stick support team on +1-844-920-4357 for any technical assistance or visit our blog on https://amazonfirestick.tumblr.com/post/184733831947/firestick-optimizing-system-storage-and.