An Unknown Sync error occurred (-54)

Re: iPhone Cannot Be Synced Error (-54)

I had the similar problem and it was related to iBooks login. I have the latest iTunes 12.3.0.44. Somehow after updating either my iMac to El Capitan or my iPhone 6S to iOs 9.0.2, I constantly get this error message when syncing my iPhone to iTunes. After several days of researching I could not find a solution. By luck, today I was syncing and I needed to look into iBooks section on my iPhones. iTunes asked me to log back into iCloud for accessing the iBooks and the error message disappeared. I suspect somehow by upgrading either iMac or iPhone it logged me out of iBooks. Hope this helps someone. Good luck.

It turns out that the logging into iBooks also fixed my error -54.

Thanks for the post.

Wow, this helped me as well. Thank you so much for posting this!

Dr. Denton

I am glad this was helpful to some of you. In my case, the error recurred a few days later and it was not related to iBooks this time. It turned out somehow my iMac was logged out of iCloud. After I logged back into iCloud the error message disappeared again. I suspect this was a bug either the new iTunes or Al Capitan. Good luck to all.

I had to log out then back in, but your method worked great, thanks for the assist 🙂

After relogin iBooks, it is fixed now. Thank you so much.

Worked for me, too. My syncs seemed to hang in the copying artwork area, so in addition to iBooks, I logged into music, just in case. Anyway, now the sync is working.

I wasn't exactly sure where I was to log into iBooks, as I wasn't sure if you were referring to the MacBook or the iOS device (I am having the same problem on an iPad Pro). Signing out of iTunes/iBooks on the Mac did nothing for me, nor did signing in and our of iBooks on the iPad Pro. Finally, I opened the App Store and signed out (scroll to the bottom of the App Store app). I logged back in, killed iBooks running in the background on the iPad, then opened iBooks on the iPad once more - I noticed that the gear spun at the top of the screen, showing that the iPad was likely phoning home to Apple that I had logged in, and a transfer of data appeared to be successful as I didn't receive a notice in iBooks on the iPad. I connected my iPad to my MacBook and opened iTunes once more and tried to transfer purchases from the iPad to the MacBook, and was successful.

I hope this clarifies things a little for someone.

I had this -54 error when trying to sync my iPhone 6s. I have no idea what changed between now and the last time i synched, except I did upgrade to 9.3.1 on the phone. I tried turning off and on my phone, tried to delete iTunes .xml, but it does not use an xml file anymore, I logged into iBooks on my iMac, and none of that worked. I decided to log out of iCloud on my iMac (that took some waiting, in Syst. Prefs), then when I tried to log back in it wanted a password with a capital letter, which my old pw did not have. So I reset the pw, jumping thru the hoops to do that, and had to re-login on my iMac and iPhone. Then I tried again to sync the phone to iTunes and it worked! Weird part of this was that Apple also wanted me to enter the new pw for my OLD Apple ID, which I thought I had deleted! So I just hit "cancel" when that window came up, and like I said this iCloud logout/ password reset reset worked for me.

I was having the exact same issues and tried all the previous fixes (logging out of iTunes, iCloud, etc). The culprit did indeed seem to be in the APP STORE. I signed out of the APP STORE out, signed in again, and that seems to have fixed the problem. 🙂 (hint, hint, Apple!)

This first happened to me a couple of weeks ago when backing up my iPhone 6 to iTunes. It looks like a permissions error but "Fix Permissions" is no longer a separate option in Disk Utility. I ran First Aid but it didn't help. I deleted the iTunes .XML file and it worked the first time but not today. I tried logging out and logging back into iBooks, iTunes, and App Store to no avail. I didn't try iCloud because I was afraid to select delete or copy my contacts. I have spent a lot time merging and linking contact records and did not want to mess with it.

UNLOCKING the iPhone before starting the backup worked!

I now wonder if deleting the .XML file didn't do anything the first time; I didn't notice if the iPhone was unlocked. Logging in and out of the various applications may seem to work for some people because their iPhones happened to be unlocked.

An official response from Apple would be welcome.

See this thread:

Attempting to copy to the disk Macintosh HD failed. An unknown error occurred (-54).

As shared by TNee, by simply unlocking the iPhone while synching, I no longer receive an error. Do you think maybe Apple could fix this????

Error -54 is the main sync error I get, and each time I've traced it to saving a PDF file (generally an email attachment) to iBooks. I have to delete the PDF file in iBooks and the error -54 goes away.

My new rule is to leave PDF files in email as attachments and not save them to iBooks.

That said, I've seen people report a gazillion other fixes to -54 so clearly this isn't the only issue.

Thanks a lot, the fact to login iBooks solved also my -54 error !!!

These iTunes errors should be more detailed !!!