we're a school using Shared iPads for our students. I've set the ResidentUser setting to 5-7 users depending on the iPads storage. Occasionally I get an iPad that won't allow any more logins, neither users nor guests. It shows an error message like this:
Not enough storage available
There is not enough storage available to add another user to this iPad. Wait until all users are synchronized or contact your admin to free up storage.
Waiting obviously doesn't help. And being the admin, I don't seem to have any tools available to free up storage. My only recourse seems to be to wipe the device.