iPhone won't sync with your Mac: error -54

Why it happens

Error -54 means something stopped your Mac reading or copying a file during the sync. Often it's one locked or damaged song, photo or file, and sometimes security software on the Mac gets in the way. The rest of the sync stops when it hits that item, so finding it is the real fix.

How to fix it

1. Restart your Mac and your iPhone. That clears a file that's stuck being used.

2. Update both. On the Mac, open General, then Software Update in System Settings. On the iPhone, go to Settings, General, Software Update.

   General›Software Update

3. Connect the iPhone with a cable, unlock your iPhone, and tap Trust if it asks. Then select your iPhone in the Finder sidebar.

   Finder›iPhone

4. Sync a little at a time. Untick most of what's selected in tabs like Music and Photos, keep one album or playlist, and click Apply or Sync. If that works, add the next batch.

5. When the error comes back, the last batch holds the problem. Narrow it down to the one song, photo or file, delete it from what you sync, add a fresh copy back, and sync again.

Still not fixed?

1. Check the file isn't locked. Select it in Finder, choose File, then Get Info, and untick Locked if it's ticked.

2. If you use security or antivirus software on your Mac, pause it for a moment and try the sync again. Turn it back on straight afterwards.

3. Try a different cable and a different USB port on your Mac. A loose connection can break a sync partway.

4. Make sure your iPhone has enough free space for what you're syncing. Check in Settings, General, iPhone Storage on the iPhone.

5. If small batches still fail with a new cable, contact Apple Support. If your iPhone also won't charge or connect on that cable, the port may need a repair.