This question is similar to others e.g. here but I still can't find a solution.
I am trying to back up my iPhone for the very first time on a brand new MacBook Pro.
When I log in to iTunes to initiate the backup I see the following message noting that there has been no backup before:
Then, if I try to turn off encryption of the backup (or indeed set a password), I see:
Does anyone know what's going on, or what I can do to back up my iPhone and then restore to a new one?