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loadedmind, Mac Support Specialist
Category: Mac
Satisfied Customers: 359
Experience:  Several years experience as consultant, corporate I.T. & sysadmin.
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Connected up brand new 1 TB external drive last night to Imac

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Connected up brand new 1 TB external drive last night to Imac using Time Machine. It seemed to be backing up the internal drive just fine as I continued to use the computer. At about 20 GB it stopped and gave an error message. Tried to reboot, hit "back up now" in Time Machine and keep going but it does not seem to function as before. Light on WD drive continues to flash slowly.

T. Sheridan [email protected]
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loadedmind :

Hi and welcome to JustAnswer - I'm John.

Can you please provide the error message Time Machine reported in its entirety?


Unable to complete backup. An error occurred while copying files to the backup volume.


Unable to complete backup. An error occurred while copying files to the backup volume.

loadedmind :

What version of OS X are you using? To obtain this information, click on the
Apple icon at top left, then choose About This Mac from the menu. The numbers to
the right of Version is what I'm looking for.



loadedmind :

Please go to Finder->Applications->Utilities and launch Disk Utility. Choose your WD external hard drive from the list on the left. Go ahead and Erase using Mac OS Journaled (Extended) and after it completes, go to Time Machine, make sure it knows to use that hard drive, then try the operation again and please let me know the results. I'll be back shortly.

loadedmind :


loadedmind and 2 other Mac Specialists are ready to help you
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Please let me know the results of your Disk Utility operation when time permits.
Customer: replied 6 years ago.
erased disk , seems to working starting over
Ok, let me know if this resolves the issue or not please. Make sure to wait until Time Machine operation is finished.
Customer: replied 6 years ago.
no, erased and started over. so far so good. Thanks
Terrific! I'll close the question then. It looks like you have a second question open currently. Is it possible the question is a duplicate from this one?

Edited by loadedmind on 7/1/2010 at 7:35 PM EST
Customer: replied 6 years ago.
Whoops. I erased the drive as per your instructions and Time Machine again proceeded to backup about 25GB and then I got the same error message "unable to complete backup. An error occurred while copying files to the backup volume." Would that be due to improper initial formatting and partitioning? I assume Time Machine would make sure that was correct. I'm now in process of doing it a third time.

If it happens again I assume I must return the drive. To Western Digital? By what procedure?
[email protected]
Hi and thanks for the info. It does sounds like, at this point, you may have issues with that hard drive. There are utilities out there that can check the integrity of the hard drive, but if Time Machine can't even use it to backup your data after you've erased it using the Mac OS Journaled (extended) filesystem type, chances are, it's defective. You'd probably want to contact Western Digital direct and ask them what their RMA procedure is. They'll probably need to open a ticket and send you information how to get that hard drive to them and they'll ship you a new one if you're within the allotted time period. I'm not sure what that is as this is different for every vendor. In any event, here's Western Digital's, contact information:

1(NNN) NNN-NNNN/td> Monday - Thursday
Friday - Sunday
8 am - 7 pm CST
8 am - 5 pm CST

From my experience with Western Digital, they may not be the most personable company for customer service, but they were efficient with me. I had to get another USB cable for my WD Passport hard drive and they expedited it once I verified my serial number.

Best of luck,