I'm currently very annoyed by the many hours that I have already invested in restoring this iPhone and am now looking for help here because I need this phone today and Apple Support can only be reached by phone tomorrow.
So here I have my old iPhone SE, which is completely locked. "iPhone is deactivated. Connect to iTunes" shows it to me so nicely and of course I immediately informed myself and since it is just an old cell phone with unimportant data on it I wanted to restore it. So I checked whether the MacBook that I want to use to do this is up to date (spoiler: it is). So now I've put it in this beautiful mode in which a charging cable, an arrow and the iTunes symbol, as well as a URL, appear on the display. Incidentally, the URL is rather less helpful.
I was immediately offered to restore it on iTunes and I gladly accepted this offer, just click on "Accept" on all windows and it was done. It would now load for an estimated 50 minutes.
So, ready to face this long charging time, I made myself comfortable and waited until after about 10 minutes my cell phone went on again and my laptop "iTunes could not connect to this iPhone. The value is missing." indicated.
That's it. So the spectacle was now almost 10 times.
I always click on "update" in the first window, then on "update & bliblablub whatever it says", in the next step I accept the terms of use for iTunes for iOS 13.something and well, the rest I know.
You're welcome.
Do you have a Mac or Windows?
A MacBook Air
