Description:
iTunes or iMazing backups never finish or are too slow:
- Backup is stuck at a specific percentage and is not progressing for a very long time
- Error message at a specific percentage
- Backup restarts on its own
- Extremely long total backup times (but backup completes successfully)
Solution:
Your first backup will take the longest; all subsequent backups are incremental and will be much quicker. The following factors can significantly impact backup times:
- Connection type (USB or Wi-Fi)
- Backup location & backup storage medium (internal, external, NAS/network; mechanical vs SSD)
- Available space on the device being backed up & at the backup location
- Files modified during the backup process
- Third-party software and security
1. Connection type
Connect your device via USB instead of Wi-Fi.
If you’re already connected via USB, try another USB port on your computer.
If possible, avoid connecting your Apple device or external drive to a USB hub, dock, or a dongle (like USB-A USB-C adapter). Direct connections to the computer are better.
Try to use the original cable that came with your device, or make sure that your USB Lightning cable is MFI-certified (Made for iPhone). Cheap alternatives can have a low data transfer speed.
If you would like to make your backups via Wi-Fi and your backups are slow, make sure that:
- You run at least the first backup via USB
- Your Wi-Fi router supports Wi-Fi 4 (802.11n), but preferably Wi-Fi 5 (802.11ac) or Wi-Fi 6 (802.11ax)
- Your computer is either connected via Ethernet to the router, or located in close proximity to the Wi-Fi access point (and also connecting at Wi-Fi 4 or faster)
- Your device is located in close proximity to your router
- If backing up to a network drive or NAS, make sure the connection between the network drive or NAS and router is also strong, or connect your network drive or NAS directly to your Wi-Fi access point or router with an Ethernet cable
2. Backup location
Backing up to an external drive, network drive, NAS, Apple Time Capsule, or other non-internal storage can take significantly longer than backing up to an internal drive.
If your backup is not finishing:
External Drive (USB or Thunderbolt)
- Make sure to connect the drive to the fastest port on your computer, either USB 3 or Thunderbolt
- Check that no other backups or file transfers are simultaneously running (pause all third-party backup software on the computer, including Time Machine if you’re on a Mac)
- Check if the drive you’re backing up to is almost full—or will be after a backup completes—the backup process can slow as the destination nears full capacity. The solution again is to free up space on the destination drive.
Network Drive / NAS / Apple Time Capsule
- Connect your networked drive or NAS directly to your computer via USB or Ethernet for the first backup (if possible)
- Make sure the connection between the drive and router is also strong, or connect your network drive or NAS directly to your Wi-Fi access point or router with an Ethernet cable
- Make sure your computer is either connected via Ethernet to the router, or located in close proximity to the Wi-Fi access point (and also connecting at Wi-Fi 4 or faster)
- Ensure that no other backups or file transfers are simultaneously occurring (pause all third-party backup software on the computer, including Time Machine if you’re on a Mac)
- Check if the drive you’re backing up to is almost full—or will be after a backup completes—the backup process can slow as the destination nears full capacity. The solution again is to free up space on the destination drive.
Note: Do not use cloud storage (OneDrive, Google Drive, Dropbox, etc.), SD cards, or USB flash/thumb drives as your backup location. These have either low read/write speed or connection issues that will corrupt the backup.
We also advise against using Western Digital (WD) My Cloud Home for backup. These are extremely inefficient NAS drives that can generate a lot of issues when backing up iOS devices. You should not back up your iOS devices to such drives.
3. Available space on device & backup location
If your Apple device has little free space left (less than 5-7% of the total device capacity, but not more than 10-15 GB), it can take much longer to back it up. Free up some space on your device, then try again.
NOTE: The storage report in Settings > General > Storage on the device won’t include purgeable space. Please make sure to check the device storage with iMazing:https://imazing.com/guides/learn-imazing-interface#disk-usage
Similarly, if the drive you’re backing up to is almost full—or will be after a backup completes—the backup process can slow as the destination nears full capacity. The solution again is to free up space on the destination drive.
4. Files modified on device during the backup process
If your device is taking a long time to back up, previously backed up files might have already changed (during the backup) and the backup process on the device will start over for those items. iOS is in charge of this process, not iMazing, which 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 Wi-Fi and Bluetooth
- Do not use the device while it is being backed up
5. Third-party software and security
A lot of third-party software can affect the backup process:
- Security software: Antivirus, firewall, VPN, or even ad-blockers can slow or interrupt the backup process, sometimes without triggering any error message (either by iMazing or with the software causing the issue). Please try to quit or pause these kinds of utilities if you are encountering backup issues. If the issues persist, you may need to uninstall the software and restart the computer.
If using third-party antivirus software, make sure to exclude your backup location from being scanned. iOS and iPadOS backups contain 10,000s of small files, and real-time virus scanners can significantly slow the backup process as it checks all these files.
NOTE: In general, antivirus software is not needed if you are running Microsoft Windows 11 or recent macOS versions, as the operating system manages threats adequately on its own.
NOTE: Even if you have used the same security software for some time on your computer—even successfully alongside iMazing backups—please keep in mind that updates can introduce new issues. If you are experiencing new issues with backups, do not skip the step of trying to disable security software, simply because it wasn’t an issue previously. - Computer backup software: iMazing backups will be more reliable if they are performed at a different time from any computer backups.
If you schedule backups automatically with your computer, please choose a time that’s different from when you may be backing up an iOS or iPadOS device. This is especially true if the location you are backing your Apple devices to with iMazing is included in your computer backup schedule, which is almost always the case if you’re backing up to a computer’s internal drive.
Backup software can also “lock” the contents of an external drive’s invisible Temp folder, which iMazing uses to store temporary backup files. If this happens, the backup will almost always fail. Popular solutions like Time Machine, Acronis, Carbon Copy Cloner, and Backblaze can all create this circumstance.
Backblaze users should pay special attention to their Backup Schedule, and make sure it is either configured to Only when I click <Backup Now> or Once Per Day. By default, Backblaze backs up Continuously, which will create issues for local iOS or iPadOS backups. - Sync software: Data that is synchronized to a device, especially by a third-party during the backup process (using Dropbox or Google Photos, for example), can cause the backup process to restart itself as it attempts to include those newly detected files on the device.
Not using your device during backup and/or placing it in Airplane mode with Wi-Fi disabled can eliminate this conflict.
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