How to Fix iPhone Update Error 14

By ErrorFix · Updated October 18, 2026 · 6 min read

What error 14 means

Error 14 shows up in iTunes on Windows or Finder on a Mac while you are updating or restoring an iPhone. The update starts normally — the progress bar may even creep along — and then everything stops with the message "The iPhone could not be updated. An unknown error occurred (14)." The iPhone usually drops back into recovery mode, showing the computer-and-cable screen, waiting for another attempt.

The "unknown error" wording is Apple's catch-all for a process that broke down without a cleaner diagnosis, and with error 14 the breakdown is almost always the file check. Before iOS is written to the phone, the computer verifies the firmware package it downloaded from Apple, and if anything about that package or the transfer looks wrong, the whole thing is aborted. That makes this a fundamentally different failure from a code like error 56: where 56 often ends at a hardware diagnosis, error 14 is a puzzle with a solution in most cases, because the culprit is usually on the computer's side of the cable rather than inside the phone.

There is one notable exception worth knowing about. A well-documented pattern ties error 14 to iPhones that were running on nearly zero free storage before the update started. A phone with no breathing room can crash mid-update and land in a state where every update attempt fails with error 14 — and since the phone will not boot, there is no way to delete photos or apps to free space first. If your iPhone was constantly at the edge of "Storage Almost Full" before this happened, keep that scenario in mind as you work through the fixes: it explains why steps that normally work can fail on a genuinely full phone.

Common causes

• Worn or uncertified USB cable: the most common cause — a cable that cannot sustain gigabytes of error-free data transfer mid-update.
• Unstable USB port or hub: hubs, docks, and front-panel ports interrupt the firmware stream with shaky power or noise.
• Corrupted IPSW download: a firmware file that arrived damaged fails the file check on every attempt until it is deleted.
• Outdated iTunes or macOS: old software mishandles the update handshake with the phone and Apple's servers.
• Security software interference: antivirus, firewall, or VPN tools blocking traffic during the update verification.
• Hardware fault or near-full storage: failing NAND flash or a phone that ran out of space mid-update produces the same code.

How to fix error 14 — step by step

Work through these in order. Steps 1 through 5 resolve the overwhelming majority of error 14 cases; step 6 is the last software option before the hardware verdict.

1. Swap the USB cable and port. Use a genuine Apple or MFi-certified Lightning or USB-C cable and plug it directly into the computer, skipping hubs, docks, and keyboard ports. On a desktop, use a rear USB port, which delivers steadier power. Then try the update again. Error 14 is very often a connection problem, and this one swap resolves most cases where the iPhone's storage is nowhere near full.
2. Restart both devices and update iTunes or macOS. Restart the iPhone by holding the Side button and a Volume button and swiping to power off, then fully restart the computer. Next, update the software on the computer: on Windows with the modern Apple apps, open the Microsoft Store, go to Library, and update the Apple Music and Apple Devices apps; in classic iTunes, choose Help and then Check for Updates. On a Mac running macOS Catalina or later, the iPhone is handled by Finder, so open System Settings, go to General, and choose Software Update. Retry the update afterward.
3. Delete the corrupted IPSW file. iTunes and Finder download an IPSW firmware file before every update, and if that download is even slightly corrupted, error 14 keeps repeating until the file is replaced. On a Mac, open Finder, choose Go and then Go to Folder, and paste ~/Library/iTunes/iPhone Software Updates; Control-click the IPSW file and choose Move to Trash. On Windows, open File Explorer, paste %appdata%\Apple Computer\iTunes\iPhone Software Updates into the address bar, and delete the IPSW file. The next update attempt downloads a completely fresh copy.
4. Temporarily disable security software. Antivirus, firewall, and VPN tools can interfere with the traffic between the computer and Apple's verification servers during an update. On Windows, open Windows Security, go to Virus and threat protection, and pause real-time protection; on a Mac, temporarily disable any third-party security or VPN software. Turn everything back on immediately after the update attempt finishes.
5. Try a different computer. Connect the iPhone to a different computer with a fresh installation of iTunes or Finder and run the update there. If the update succeeds on the second computer, the fault is with the first machine's USB ports, drivers, software, or security configuration, not with the iPhone itself.
6. Do a DFU-mode restore as the last software option. If error 14 keeps appearing, put the iPhone in DFU mode: connect it to the computer, press and quickly release Volume Up, press and quickly release Volume Down, hold the Side button for 10 seconds, then, while still holding Side, hold Volume Down for 5 seconds. Release the Side button but keep holding Volume Down for about 10 more seconds. The screen stays black, which confirms DFU mode. iTunes or Finder will offer to restore the device, erasing it and reinstalling iOS cleanly. Restore your data from an iCloud or computer backup afterward.

Did this fix it? Quick checklist

• A certified cable plugged directly into a rear or built-in USB port
• The IPSW firmware file deleted so a fresh copy downloads
• iTunes or Finder and the computer's OS fully updated, security software disabled
• The update attempted on a second computer without success

If error 14 still appears after all of that, the remaining explanations are narrow: a phone that was updated on nearly zero free storage, or a genuine hardware fault — most commonly failing NAND flash that can no longer hold the firmware image. Take it to an Apple Store or an Apple Authorized Service Provider, mention error 14 by name, and be honest about the storage situation and any drops or liquid exposure. And confirm you have an iCloud or computer backup of anything irreplaceable before you go, because a DFU restore or board-level repair means the data on the phone is gone.