iOS 10.1 missing storage space
I've similar issue on my iPad mini 2 for quite a while. I'm not sure what caused it, but have read that iOS would free spaces when needed. That means, the free space we see in the settings is actually not accurate. There are some disk cleaning apps and should "force" iOS free the spaces. I am using an app called "memory &amp; disk scanner pro", and it can do the job. You may try it or some other similar apps.