How to Fix iTunes Error 1644 When Restoring iPhone
What error 1644 means
Error 1644 is an iTunes or Finder error that appears while an iPhone is being restored or updated through a computer. The restore starts, the software prepares or downloads, and then the process stops with a message that the iPhone could not be restored and an unknown error occurred (1644). Your iPhone is usually left in recovery mode, showing the computer-and-cable screen, waiting for another attempt.
Apple groups error 1644 with errors 1643 to 1650, and that whole group points to the same area: the USB cable, the USB port, or the computer. That is a useful distinction, because other restore errors point elsewhere. Errors in the 3000 range, for example, usually mean the computer could not reach Apple's update servers, while 1644 means the local link between the computer and the phone broke down. Knowing which family your error belongs to saves a lot of wasted effort, since a hosts-file fix will not help a cable problem, and a new cable will not help a server problem.
In older iTunes documentation, error 1644 was also tied to the firmware file being moved while iTunes was preparing it. That is the same idea in different words: the restore needs a stable, uninterrupted read of a large firmware file and a stable USB connection for the whole process. Anything that disturbs either one, a loose cable, a hub that drops power, a computer that goes to sleep, or a file that gets moved, can stop the restore with this code. The iPhone itself is usually fine, which is why the fixes below start with the cable and the computer rather than with the phone.
Common causes
- Faulty or uncertified USB cable: a damaged, worn, or cheap third-party cable that drops the connection under load during a long restore.
- Weak USB port or hub in the chain: keyboard ports, hubs, and docking stations that cannot supply steady power and data for the whole restore.
- Interrupted firmware download or file: a firmware file moved, renamed, or cut short by a lost connection or a computer going to sleep.
- Outdated iTunes, Finder, or computer software: old restore software that mishandles the connection or the firmware verification step.
- Security software or a failing port: antivirus or firewall tools interfering with the restore, or, more rarely, a damaged iPhone port or storage fault.
How to fix error 1644 — step by step
Start with the cable and the port, since that is where most 1644 cases are fixed. Work down the list in order.
- Switch to a genuine cable on a direct USB port. Use the cable that came with the iPhone, or another Apple or MFi-certified cable, and plug it straight into a USB port on the computer itself. Remove USB hubs, keyboard ports, extension dongles, and docking stations from the chain, because a weak or interrupted connection is the most common trigger for error 1644. If the restore gets further with the new cable and port, the old cable or hub was the problem.
- Restart the computer and the iPhone, then retry. Shut the computer down fully rather than just putting it to sleep, and restart the iPhone if it is responsive. Reconnect the phone only after both devices have fully restarted, then start the restore again. A fresh start clears temporary USB and driver glitches that can interrupt a restore partway through, and it costs nothing to try before moving to deeper fixes.
- Update iTunes, Finder, and the computer software. On Windows, open the Microsoft Store, go to Library, and install updates for the Apple Music and Apple Devices apps, or in classic iTunes go to Help and choose Check for Updates. On a Mac running macOS Catalina or later, restore from Finder and open Apple menu, System Settings, General, Software Update to install any pending macOS update. Restart the computer after updating, then retry the restore with the current software.
- Let the firmware download finish without interruption. Once the restore begins, do not move, rename, or open the firmware file, do not unplug the cable, and do not let the computer go to sleep or lose its internet connection. The firmware file is large, so a slow connection can take a long time, and interrupting it partway through is a documented cause of error 1644. If the download was interrupted before, restart the restore so iTunes or Finder fetches a fresh, complete copy.
- Temporarily disable security software and try another computer. Antivirus and firewall tools can interfere with the USB connection and the restore process, so turn them off briefly, retry the restore, and turn them back on as soon as the attempt finishes. If the error still appears, try a different computer with a fresh iTunes or Finder install and a known-good cable. A successful restore on the second computer proves the iPhone is fine and the first computer's setup was the blocker.
- Restore from recovery mode with the latest iOS. Put the iPhone into recovery mode, connect it to the computer, and choose Update first, which reinstalls iOS without erasing your data. If Update fails with 1644 again, choose Restore, which wipes the iPhone and installs the latest signed iOS version. If error 1644 still appears after a clean restore on a second computer with a genuine cable, contact Apple Support, since a repeated failure points to a hardware problem with the phone or its port.
Did this fix it? Quick checklist
- Genuine Apple or MFi-certified cable plugged directly into the computer, no hub or keyboard port
- iTunes or Finder and the computer software fully updated, both devices restarted
- Firmware download left alone until it finished, security software re-enabled after the test
- The restore or update completes without 1644 (or Update in recovery mode succeeds)
If 1644 survives a genuine cable, a direct port, updated software, a second computer, and a clean firmware download, stop retrying the same setup. The pattern points away from your equipment and toward the phone itself. Confirm you are installing the latest signed iOS version, check Apple's System Status page, and contact Apple Support with error 1644 in hand; it places your case straight into the USB and connection family of restore errors.
Frequently asked questions
What does iTunes error 1644 mean?
It means the restore was interrupted because the computer lost a reliable connection to the iPhone or the firmware file was disturbed during the process. Apple groups error 1644 with errors 1643 to 1650, which all point to the USB cable, USB port, or computer rather than to Apple's servers, so start with the cable, port, and computer before suspecting the phone itself.
Is error 1644 caused by a broken iPhone?
Usually not. Most 1644 cases are fixed by a genuine cable, a direct USB port, updated software, or a second computer. Only if the error repeats on a second computer, with a second genuine cable, on a different port, and with the latest signed iOS should you suspect a hardware fault in the iPhone's port or internal storage, and at that point Apple Support or an authorized repair is the right next step.
Can I fix error 1644 without losing my data?
Often yes, because the cable, port, and software steps do not touch your data at all. In recovery mode, choose Update rather than Restore: Update reinstalls iOS without erasing anything. Only Restore wipes the iPhone, so treat it as the last step, and restore your data afterward from an iCloud or computer backup made before the problem started.
Why should I not move the firmware file during a restore?
Because iTunes and Finder read the firmware file while the restore is running, and moving, renaming, or opening it can break that read and stop the restore with error 1644. Leave the computer alone once the restore starts: keep the cable connected, keep the internet connected, and do not let the computer sleep until the process finishes or fails on its own.
What if error 1644 appears on every computer I try?
Then the problem is likely the iPhone, the cable, or the firmware build rather than any one computer. Try a second genuine cable and a direct port, confirm you are installing the latest iOS version Apple currently signs, and check Apple's System Status page for any outage. If it still fails everywhere, contact Apple Support and mention error 1644, which places your case in the USB and connection family of restore errors.