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decafjava

macrumors 603
Original poster
Feb 7, 2011
5,388
7,769
Geneva
I've been getting a strange error pop-up for awhile now every time I back-up/sync to iTunes. At the end a pop-up comes up saying "Can't write to Macintosh HD unknown error -54" but it syncs apps and updates my palylists fine. It also makes a backup (it says backup was last created xxx) with no problem. Only other thing is the apply button appears as well though when I click it it goes away. BTW I make full encyrpted backups.

Not sure what the issue is - I had this problem briefly on my old computer last month but it never seemed to affect anything either?
 

keysofanxiety

macrumors G3
Nov 23, 2011
9,539
25,302
Contrary to the above, I can't find lots of information about unknown error -54 when Google searching, so looks like we'll have to run some old fashioned troubleshooting. Otherwise if Newtons can point us to the fix, that'd be pretty dandy.

A possible fix (as it's a write error) would be to right-click Macintosh HD on your desktop, select 'Get Info', click the padlock at the bottom right, then the plus at the bottom left, and select your user account. Then ensure the Privilege level is set for Read & Write.

If Macintosh HD doesn't appear on your desktop, single click the desktop background and select Finder> Preferences in the top left, General, and tick Hard disks for Show these items on the desktop.

However if we could get a bit more information about the setup, that may be helpful. Do you use Wi-Fi backups or do you backup using a cable? If you use a cable, does the problem persist with a different cable? Do you have FileVault enabled on your Mac? Can I also check what OS version you're running?

Best wishes & speak with you soon.
 
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decafjava

macrumors 603
Original poster
Feb 7, 2011
5,388
7,769
Geneva
Contrary to the above, I can't find lots of information about unknown error -54 when Google searching, so looks like we'll have to run some old fashioned troubleshooting. Otherwise if Newtons can point us to the fix, that'd be pretty dandy.

A possible fix (as it's a write error) would be to right-click Macintosh HD on your desktop, select 'Get Info', click the padlock at the bottom right, then the plus at the bottom left, and select your user account. Then ensure the Privilege level is set for Read & Write.

If Macintosh HD doesn't appear on your desktop, single click the desktop background and select Finder> Preferences in the top left, General, and tick Hard disks for Show these items on the desktop.

However if we could get a bit more information about the setup, that may be helpful. Do you use Wi-Fi backups or do you backup using a cable? If you use a cable, does the problem persist with a different cable? Do you have FileVault enabled on your Mac? Can I also check what OS version you're running?

Best wishes & speak with you soon.
Didn't find much helpful advice either which is why I asked. I'll certainly try the option of checking the privilege level.

I always back-up with a cable and although it looks fine it I'll try the newer one that came with my still new iMac.
I don't think I have FileVault enabled, never heard of it actually. I use MacOS Sierra with the latest update as well.

I'll try what you suggested and report back this evening.
 

posguy99

macrumors 68020
Nov 3, 2004
2,282
1,531
A possible fix (as it's a write error) would be to right-click Macintosh HD on your desktop, select 'Get Info', click the padlock at the bottom right, then the plus at the bottom left, and select your user account. Then ensure the Privilege level is set for Read & Write.

Uh, no. Just no. Gods save us from people who recommend making random permissions changes to system drives.
 

keysofanxiety

macrumors G3
Nov 23, 2011
9,539
25,302
Uh, no. Just no. Gods save us from people who recommend making random permissions changes to system drives.

It's not like the suggestion was to enable the root user.

Just to reassure you: changing the permissions on Macintosh HD doesn't suddenly grant R&W access to every sub-folder on the volume. Not even the Users folder. Any changes to system folders would still prompt for the user password; and in 10.11+, SIP prevents any changes whatsoever.

It's a pretty specific permission change for a specific user, specifically for troubleshooting; if it works, I'm sure we can revert the changes and whittle down what needs to be done if necessary.

Of course you can never be too careful! As the error seems to be permissions related, if you would suggest changing the permissions on a different folder, we can happily try that suggestion first and work backwards from there.
 
Last edited:

decafjava

macrumors 603
Original poster
Feb 7, 2011
5,388
7,769
Geneva
Well I tried it and it didn't do anything.

However the problem was elsewhere - it turns out I had synced an album (of wallpapers) from my computer that I could not delete from my phone as I had turned photo sync off. Turned it on, deleted the photo album and it synced and backed up fine!

So should I turn off my user permission to read and write? I am somewhat new to Mac and would think as the main (only) user and admin I should keep it or revert??
 

keysofanxiety

macrumors G3
Nov 23, 2011
9,539
25,302
Well I tried it and it didn't do anything.

However the problem was elsewhere - it turns out I had synced an album (of wallpapers) from my computer that I could not delete from my phone as I had turned photo sync off. Turned it on, deleted the photo album and it synced and backed up fine!

So should I turn off my user permission to read and write? I am somewhat new to Mac and would think as the main (only) user and admin I should keep it or revert??

Hey, glad the issue's resolved. :)

Yeah just go back into the Get Info, unlock the padlock, highlight your user and then click the minus (-) arrow at the bottom left to remove.
 
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