iOS 9 backup bug
I have found that since updating to iOS 9; my iCloud backup has been deleted and the new backup is messed up.
iOS doesn't seem to recognise the amount of data an app will take up; on manage storage under the backup it says every app is no data. I've noticed since turning off all 350 apps and leaving just one switched on that the backup then works but and the apps now only show data that is already backed up.
SO Apple have 2 bugs: iOS 9 deleted your old backup. And iOS 9 the backup space prediction is all messed up; making adjustments basically resets the next backup size to 0 bytes and lost option to see what data will be backed up to reduce your backup size.
I Awoke this morning horrified that I had a backup failed warning and that back said last backup: never !!!
ABove image what I woke up to
below image is after a backup with small apps
iPhone 6 Plus, iOS 9