How to Fix iTunes Sync Error 54 (Files Could Not Be Synced)

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

What error 54 means

Error 54 appears while syncing an iPhone with iTunes on Windows or with Finder on a Mac. The sync starts, a progress bar moves through your content, and then it stops with a message like "The iPhone cannot be synced. An unknown error occurred (54)" — sometimes naming the specific files that could not be synced. Unlike the restore-time codes such as 9 or 56, error 54 is strictly a sync problem: it happens when media files are being copied between the computer and the phone.

The good news is that error 54 almost never means hardware is failing. It means iTunes hit a file it could not read, write, or locate. Common triggers include a song that is open in another app (which locks the file), a media folder marked read-only after a Windows update, a library file that references a track moved to a different folder, a stale authorization record after you changed your Apple ID password, or a single corrupted file that crashes the copy. Because the sync aborts instead of skipping, one bad file can hold the entire library hostage.

The fix strategy is therefore a process of elimination rather than a single magic button. You clear the cheap possibilities first — restarts and re-authorization take minutes and resolve the majority of cases — then narrow down the failing files by syncing in smaller batches, and finally repair the underlying permissions or library structure so the problem does not come back next week. Work through the steps in order; most people never need to go past step 4.

Common causes

• File locked by another program: a track open in a music player, editor, or cloud sync tool cannot be read for copying.
• Read-only media files or folders: Windows updates sometimes flip media folders back to read-only, blocking writes.
• Stale computer authorization: password changes or major updates can break the authorization record iTunes relies on.
• Broken library references: tracks moved, renamed, or deleted outside iTunes leave pointers to files that no longer exist.
• A single corrupted or DRM-mismatched file: one bad track can abort the entire sync instead of being skipped.

How to fix error 54 — step by step

Work through these in order. Steps 1 and 2 clear the temporary and account-side causes that account for most error 54 cases; steps 3 through 6 dig into the file and permission problems that remain.

1. Restart everything and retry the sync. Shut down the computer fully, restart the iPhone by holding the Side button and a Volume button and swiping to power off, then power both back on. Reconnect with a known-good cable and run the sync again. A fresh restart clears file locks held by background processes, and that alone resolves error 54 when the cause was temporary.
2. Deauthorize and re-authorize the computer. In iTunes or the Apple Music app, open Account, choose Authorizations, and select Deauthorize This Computer, then sign back in and choose Authorize This Computer. On a Mac, the same options live under Account in the Apple Music app. Authorization records can go stale after password changes or major updates, and re-authorizing rebuilds the record that lets protected files sync.
3. Deselect the items that refuse to sync. Select the iPhone in iTunes or Finder, go through the Music, Movies, TV Shows, and other tabs, and uncheck the specific items that were listed as failing. Sync the rest of the library first. Once the main sync succeeds, re-check the problem items a few at a time to identify the corrupted or locked file that was triggering error 54.
4. Consolidate the iTunes library files. In iTunes, choose File, then Library, then Organize Library, and tick Consolidate files. This gathers scattered media files into the iTunes Media folder and repairs broken file references that make individual tracks unsyncable. After consolidation, close iTunes completely, reopen it, and run the sync again.
5. Fix locked files and folder permissions. Find the tracks that fail and check whether the files are marked Read-only or are open in another app. On Windows, right-click the iTunes Media folder, open Properties, and clear the Read-only attribute, then apply to all subfolders and files. On a Mac, select the folder, press Command-I, and confirm your user has Read and Write access under Sharing and Permissions. Then retry the sync.
6. Run iTunes with elevated permissions. On Windows, right-click the iTunes shortcut and choose Run as administrator, then attempt the sync from that elevated session. If the sync succeeds there but fails normally, the underlying cause is a permissions problem on the media folder or the iTunes Library files. As a lasting fix, take ownership of the iTunes folder or move the media library to a location your user account fully controls.

Did this fix it? Quick checklist

• Both devices restarted and the sync attempted with a good cable
• Computer deauthorized and re-authorized under the correct Apple ID
• The failing items identified by syncing in smaller batches
• Library consolidated and media folder permissions set to full control

If error 54 still appears after all of that, the remaining suspects are rarer: antivirus quarantining media files mid-copy, a deeply corrupted iTunes Library.itl file (rebuild it by holding Shift while launching iTunes and choosing Create Library, then re-adding your media), or a failing drive sector on the computer corrupting new copies. Check your security software's quarantine log first — it is the most common of the three — before rebuilding the library.