As a solution to correcting iOS 10 error 14, it is suggested to backup your data, then set the device to "clean" of iOS 9 and since it upgrade to iOS 10. After this procedure, the data recovery process from a backup should pass without problems. Unfortunately, "shall" - not to "pass." Someone proposed a way to really help, but many users still get the notorious mistake. One and universal solutions do not yet exist.
It's not strange situation, because all new iOS betas have lots bugs and errors. If you have iOS 10 supported device, you can try new iOS 10 on your device, but you must understand that first betas like iOS 10 beta 1 have bags. I always use betas only on special iPhones or iPads.
If you have problems with new iOS, you always can make downgrade from iOS 10 to iOS 9.