iTunes or iMazing backups never finish:
- error message at a specific percentage
- backup restarts on its own
- extremely long backup times
Your first backup will take the longest; all subsequent backups are incremental and will be much quicker. The following factors can significantly affect backup times:
- Connection type (USB or Wi-Fi)
- Backup location (local, external, or network drive)
- Available space on the device being backed up
- Files modified during the backup process
Connect your device via USB instead of Wi-Fi.
Backing up to a network drive or Time Capsule can take significantly longer than local or external drives backups. If your backups to a network drive are not finishing:
- Connect to your network drive via cable for the first backup (if applicable)
- Make sure that no other simultaneous backups are occurring (pause Time Machine for example)
Available space on device
If your device has little free space left (less than 2 GB), it will take much longer to back it up. Free some space on your device, then try again.
Files modified during the backup process
If your device is taking a long time to back up, files previously backed up might have already changed and the backup process on the device will start over. This happens iOS side - it is a vital part of ensuring a backup's coherence and integrity.
To prevent file modifications during the backup:
- Put the device in Airplane Mode and disable its Wi-Fi connection
- Do not use the device while it is being backed up