iOS 11 or later
Removing an unwanted backup encryption setting has become easier under iOS 11 and later versions. See Turn off backup encryption for details. Your device needs to be working and able to backup to iCloud, or you need to be prepared to reset all settings on the device. The steps are as follows:
- On yourdevice, go to Settings > General > Reset.
- Tap Reset All Settings and enter your device passcode.
- Follow the steps to reset your settings. This won't affect your user data or passwords, but it will reset settings like display brightness, Home screen layout, and wallpaper. It also removes your encrypted backup password.
- Connect your device to the Finder or iTunes again and create a new encrypted backup.
An alternative method is to backup to iCloud, and then restore from iCloud.
Note these steps won't give you access to existing encrypted backups, but they will let you take control of those made in future.
iOS 10 and earlier, or you're not able to backup to iCloud
The only way to use an encrypted backup, or turn off backup encryption if currently enabled, is with the password that was entered when it was set up. The setting is stored on the device itself, so persists even if you delete your current backup set or switch to a new computer. If you have forgotten the password, or were not aware that encryption had been enabled, consider that it might be any computer, Apple ID, Wi-Fi password or device PIN that you've used in the past, working from the assumption that you might have reused a common password that you were using when encryption was first activated. See About encrypted backups on your iPhone, iPad, or iPod touch - Apple Support for details.
Having a Microsoft Exchange email account on your device will force iTunes to make encrypted backups. There could be other routes that enforce this policy setting.
If you want to turn off encryption going forward you can either erase and set up as a new device, or backup the current state of the device to iCloud, then subsequently restore from it. Non-iTunes media will need reloading from your computer once the restore is complete. See How to back up your iPhone, iPad, and iPod touch - Apple Support for details. Obviously this approach is only helpful if your device is currently functioning correctly. If you have content on your device that isn't in your library see Recover your iTunes library from your iPod or iOS device. It is also a good idea to copy everything out of the camera roll and, where possible, copy off data held in File Sharing or save important projects to iCloud Drive so that if you are unable to restore the backup you have at least minimised any data loss.
If you are still running iOS 10, your device supports iOS 11 or later, and you don't mind losing access to any 32-bit apps, then upgrading to iOS 11 or later and then using the first method is an easier course of action.
See also:
