The last backup could not be completed.
This message may occur if you back up your iOS-Device on iCloud.
It’s unrewarding like many other error messages shown on any devices.
I get this message every time I delete the last iCloud backup for my iPad or iPhone going to Settings – iCloud – Storage + Backup – Manage Storage – (device name) – Backup options: Delete Backup
It never occurred on any later incremental backup regardless of whether it was started manually or automatically.
At the time you cannot find any support document on Apple’s support website explicitly mentioning this error message.
Apple never publishes support documents about not fully investigated issues.
For the protection of our customers, Apple does not disclose, discuss, or confirm security issues until a full investigation has occurred and any necessary patches or releases are available.
So it is not fully investigated and there are many potential reasons for failing backups.
If the involved hard- and software works normally and there is enough free space in iCloud it’s usually a problem of accessing one or more files on the device or on Apple’s servers.
As iCloud backup is an incremental backup access problems are rather likely especially for temporary files created by iOS apps. This problem is well-known also on Windows PCs (Office leaves a temporary beginning with ~).
An incremental backup is one that provides a backup of files that have changed or are new since the last incremental backup; it is one that backs up only the data that changed since the last backup. When a full recovery is needed the restoration process would need the last full backup plus all the incremental backups until the point-in-time of the restoration. Incremental backups consume minimum storage space and are quicker to perform than differential backups.
A test from Jan, 2013 …
The test environment
- Backup of data of all apps configured
- iPad and iPhone both connected to power supply
- Backup size: iPhone 1.9 GB / iPad 2.7 GB
- Backup started simultaneously on both devices
The results …
On both devices the error message was displayed.
After repeating ‘Back Up Now’ the error was still displayed on both devices.
After rebooting both devices and repeating both backups one after another both backups were completed successfully.
While backing up iPhone showed a reminder, got 2 new mails and one phone call.
Nevertheless the backup was completed successfully.
Solutions from forums around the world …
- Do not include data stored in the Camera Roll
Settings – iCloud – Storage + Backup – Manage Storage – (device name) – Backup options – switch the slider to off
- Restore the device from an iTunes backup and start the iCloud backup
- Exclude data of ALL apps and back up
Add data of apps back one by one and back up manually to find out the offending app
This process may last until Apple presents its new device!
Best practice …
Do not believe all these statements in the forums.
They are all not really verified and based on special prerequisites and therefore not necessarily valid.
I start a manual backup every month since the release of iOS 5 after deleting the backup via Settings – iCloud – Storage + Backup – Manage Storage – (device name) – Backup options: Delete Backup. The following procedure works since more than one year.
Reboot the device and start a backup manually while the device is connected to the power supply and locked. If the backup fails repeat it. If it fails one more time repeat it.
Don’t worry. Retaking a backup will only last some minutes unless there is already stored data of former attempts.
When you back up the device shows an estimated time to finish.
You should know that these minutes are measured in DAMs (Dynamical Apple Minutes).
An Apple Minute may last an old fashioned minute or two or just 30 seconds.
Reducing space of backups
- Settings – iCloud – Storage + Backup – Manage Storage – (device name) – Backup options: Exclude data of apps you do not need any longer.
- Settings – iCloud – Storage + Backup – Manage Storage – (device name) – Backup options: Delete Backup
Current backup sizes: iPhone 1.6 GB/iPad 3.2 GB
Backup sizes after deletion: iPhone 1.2 GB/iPad 2.5 GB
Deleting the complete backup for my 2 devices saved 1.1 GB
Rebooting an iOS-Device
Press Sleep/Wake button and Home button simultaneously.
Keep holding the buttons until the Apple logo appears.
Release the buttons.