I have always backed up my iPhone through iTunes but I decided to use iCloud now as well. I only have the free iCloud plan with 5 GB of storage (of which 4.5+ GB free), and I'm attempting to backup an iPhone 7 with iOS 11.0.
I tried enabling iCloud backup but I got back the message: "This iPhone cannot be backed up because there is not enough iCloud storage available."
According to this fairly old Ask Different answer and this Apple support document, there should be a "Choose Data to Back Up" option to allow me to disable specific items to backup (e.g. camera roll which should be enough to allow my backup to proceed). Unfortunately I can't see this option when following the Apple support document's steps for iOS 11. When going into Settings -> my name -> iCloud -> Manage Storage -> Backup, this is the screen that shows up:
According to the support document I should now select the iPhone I want to backup, but as can be seen, there is no such option. I speculate this is because I never completed any backups at all. Thus I can't tick off items taking up lots of space to get the backup to complete for the first time.
How do I access the list of items to back up, so I can tick off some items to get the backup small enough to fit the available space?
Best Answer
I also recently noticed that the backup "choose data to back up" section doesn't show up in iOS 11 unless you have an existing backup to select first, since the UI is tucked into the screen when you select a backup for a phone.
If you're willing to go forgo the 99 cent subscription fee for a month, you could increase your storage for iCloud, make a backup, see if you can refine the backup to fit back into the 5GB limit, make a new backup, and then bring your storage plan back down.
I did the first few steps myself, and the backup refinement options do appear in the new backup. I've just been too lazy to followup and actually trim my backup to downgrade my storage plan.
Alternatively, you could go into Settings > General > iPhone Storage, and see if you've got some easy targets using a lot of Documents & Data storage to delete to bring down the size of the backup. Only Documents & Data matters for third party apps, since the apps themselves are not backed up, only the app data (documents & data) is backed up. Also iOS itself is not backed up, only the settings and user data within.