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Time Machine says "preparing" but never backs up

980 Views 15 Replies Latest reply: Apr 3, 2012 8:46 AM by Leslie Goldberg RSS
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Leslie Goldberg Calculating status...
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Mar 26, 2012 1:28 PM

I have been using Time Machine on a MacBook Pro for months to back up to a LaCie back up drive. All worked fine until January--since then, when TM is scheduled to back up, I get a "preparing" message that can run for hours, and eventually (though not always) I get an error message. I typically back up through a wireless network (TM creates a Sparsebundle) but I also tried connecting my laptop directly to the back up drive and that doesn't work either. As far as I can tell, there is nothing wrong with the laptop's hard drive--and there is plenty of room on the back up drive for all the content. MacBook is running OS X 10.5.8.


I know there is nothing wrong w/the back up drive b/c my other computer--a 27 inch new desktop--backs up fine.


Any suggestions? Thanks!

iMac Intel duo 20-inch, Mac OS X (10.5.6), Also own iMac G5 1.33 Ghz and iBook G4 laptop
  • epertak Calculating status...



    Let's give this shot:


    1. Open your Finder.
    2. Browse to \Library\Preferences
    3. Locate the preference file "", and move it to the trash.
    4. Restart your Macintosh.
    5. Reconfigure your Time Machine preferences in System Preferences.


    What this effectively does is it resets the configuration preferences for Time Machine. Please do keep me posted on the status of your issue.


    I'm eagerly looking forward to your response!

  • Pondini Level 8 Level 8 (38,710 points)

    Leslie Goldberg wrote:

    . . .

    I get a "preparing" message that can run for hours,

    See #D1 in Time Machine - Troubleshooting.



    and eventually (though not always) I get an error message.

    What message?  See #C2 in the same link.  It will show you how to locate the message(s) that describe the problem, then help you fix it.    If that doesn't help, post back with details, including all the messages, your setup, what you've done, and the results.


    I typically back up through a wireless network (TM creates a Sparsebundle)

    To an external HD connected to what?  Another Mac?  An Airport Extreme?  Or is the Lacie a NAS (network) drive?

  • epertak Level 1 Level 1 (10 points)

    Not a problem Leslie!


    Allow me to further clarify


    1. Open your Finder - And locate your main drive (By default it will be Macintosh HD).
    2. Once located, double click it.
    3. When double clicked you should see four folders: Applications, Library, System, Users.
    4. You will want to navigate into Library.
    5. Then navigate into the Preferences folder.
    6. Locate the file "" and move it to the trash.
    7. Restart your Macintosh.
    8. Reconfigure your Time Machine preferences in System Preferences.


    My apologies I should have been a little more clear on point number 2 in my initial response... In UNIX speak "\" refers to as root, which in this case would be your Macintosh HD, or whatever your main hard drive is called.


    Please do keep me posted, and don't hesitate to let me know if you require further clarification, or have any further questions.


  • Pondini Level 8 Level 8 (38,710 points)

    Leslie Goldberg wrote:

    . . .

    I have tried to back up the laptop both via the wireless network in my home AND through a hard wire USB cable connecting laptop directly to the backup drive.

    You can't do it both ways to the same drive successfully, as the backups are stored differently when they're done over a network.  See the blue box in Time Machine - Frequently Asked Question #17 for details.



    Neither has worked. I haven't tried a FireWire cable from laptop to back up drive b/c I don't have a cable that's compatible to my laptop. But I can buy one if you think this will solve the problem (I think that's unlikely).

    That's probably correct, although it's possible the USB port or chip in.  By the way, you can get a F/W 400-to-F/W 800 connector, like this: =UTF8&qid=1332857586&sr=8-1




    But no OTHER error message to tell me what the error is that's occurring.

    Are you getting that exact message (with "An error occured while creating the backup folder")?  If so, see #C10 in Time Machine - Troubleshooting.


    If not, see if the message is listed in #C2, under the sample.  If it isn't, see if it's listed in section C of the article.


    If not, get the Time Machine Buddy messages per #A1 there, and copy and post them here.

  • Pondini Level 8 Level 8 (38,710 points)

    Leslie Goldberg wrote:

    . . .

    Starting standard backup

    Mounted network destination using URL: afp://Leslie%20Goldberg@Leslie%E2%80%99s%20iMac._afpovertcp._tcp.local/Leslie's %20Back%20up

    Ah, it's a Network (NAS or Network Attached Storage) drive, not a plain external HD.  That complicates things, as each NAS has it's own mini-operating system that has to interact with OSX and Time Machine and, of course, they're all different.


    As odd as it sounds, if you can, try changing the name of the LaCie -- it has some odd characters in it, shown as "Leslie%E2%80%99s%20iMac" in the message above.  Use only numbers and letters if possible.  Odd characters and punctuation occasionally cause intermittent problems.


    Error writing to backup log.  NSFileHandleOperationException:*** -[NSConcreteFileHandle writeData:]: Input/output error

    . . .

    I don't know what the input/output error means or how to fix it.

    It's hard to tell just what's going on -- TM makes a (hidden) log in each backup folder, and that's what it's having a problem writing to.  Usually, there's a better message, and the backup fails, but this one seems to be trying to continue.  It seems to be a problem with the connection, or something on the NAS, but it's hard to tell for sure.


    I'd start by trying to repair the sparse bundle, per #A5 in Time Machine - Troubleshooting, but I doubt that will help.


    While you're at it, you might want to run Verify Disk on your Mac's internal HD, just to make sure there isn't a problem there. 


    I am wondering if I should dump the ENTIRE sparsebundle on the backup drive and start again.

    If the repair doesn't work, that's about all you  can do. See below. 


    Problem is, if I dump the whole sparsebundle, then I have NO back up at all on this machine if that doesn't solve the problem.

    Correct.  It's always prudent to keep "secondary" backups;  even more so when the main ones are on a network, and especially if there's any doubt at all.  See Time Machine - Frequently Asked Question #27 for some suggestions.  I'd strongly recommend getting an external HD and using CarbonCopyCloner or SuperDuper to make backups of all your Macs periodically, just in case there's a problem with Time Machine or your NAS.  If you do that first, you'll at least have a backup of the current contents of the Mac.


    If I dump TM, I don't know how to reload it.

    You just start fresh.  If your NAS has separate accounts (may be called "shares" or something else) for each Mac's  backups, you may be able to erase or delete the one for the Mac in question.  If all the sparse bundles are in the same area, you can probably delete the one in question, via the Finder.  If it seems to be taking forever, see the workaround in the blue box of #Q5 in Using Time Machine with a Time Capsule.


    Any additional help would be appreciated before I bag it and go to the Apple Store--though I don't know if they will be able to solve it! THANK YOU!

    It's worth a shot, but they don't get a lot of training on Time Machine (and it isn't used in the stores), plus they're not likely to be familiar with a Lacie NAS.


    You might want to contact LaCie, though.

  • Pondini Level 8 Level 8 (38,710 points)

    Leslie Goldberg wrote:

    . . .

    I'm not sure what you mean about a NAS network (sorry for my ignorance). I *DO* have a plain external LaCie 2TB Hard Drive. It is attached to my 27 " Mac. In my home, I have a wireless network and I "mount" the LaCie external back up on the laptop in order to back up using TM.

    Ah, ok, that clarifies it.  


    In that case, check the Computer Name of the iMac, via System Preferences > Sharing -- that's what's in the message above.  I doubt that's the problem, but you never know.


    In addition, I also tried PHYSICALLY connecting the laptop via a USB TO the external LaCie back up HD and that didn't work either.

    Yes, that should work, with the exception that you won't see the backups via Enter Time Machine that way; you'll have to manually mount the sparse bundle first.


    Also, I have run Verify Disk on . . . the back up drive).

    That's good, but not enough.  That doesn't check the file system inside the sparse bundle disk image (it's kind of a disk-within-a-disk).  You need to locate and double-click it via the Finder to mount it, then select it in Disk Utility and run Repair Disk on it, per #A5 in Time Machine - Troubleshooting.



    Is there a good way (other than just copying a million photos to disk) to back up photos and music from the laptop until I resolve this? I'm not currently on the Cloud (and wouldn't have enough space there anyway).

    It's always prudent to keep "secondary" backups, and especially when the primaries are on a network.  See Time Machine - Frequently Asked Question #27 for some suggestions.

  • Pondini Level 8 Level 8 (38,710 points)

    Leslie Goldberg wrote:

    . . .

    which makes me think there are some corrupted files or something.  I know that there is nothing wrong with the LaCie #1 b/c I've run disk utility on it AND it backs up the iMac with no problem.

    Do you mean you ran Repair Disk on the sparse bundle, and it said it "appears to be ok"?  If not, try that first.


    The problem seems to be on the backup disk or in the sparse bundle -- that's where the I/O errors are, when trying to write to the log there.


    If Repair Disk said the sparse bundle is ok, but you keep getting the I/O errors, you might want to connect directly to the drive, mount the sparse bundle by double-clicking it, then double-click the disk image to open it.  Inside should be a single Backups.backupdb folder, containing a single folder named for your Mac.  Inside that are the date-stamped backup folders, plus a Latest alias, and probably an ".inProgress" package.  Delete the ".inProgress" package and empty the trash.  That may take a while.  Then try another backup.



    --I was thinking I should delete ALL back ups on the LaCie #1 and start over. Does this make sense to you? If so, should I do a hard wire connection or over the home network? (I'd LIKE to have the laptop be able to back up over the network)

    If they're on a separate partition, you can just erase it.  If not, you'll have to delete the sparse bundle.  If you do that, do it while connected directly to a Mac -- it will be much faster. 


    When you do the first backup, either connect via Ethernet or follow the procedure in the green box of Time Machine - Frequently Asked Question #22 to do most of it while connected directly.  (If you skip the workaround, and do the first backup via USB or F/W, they won't be recognized via the network, and TM will start fresh.)


    --Do you think this might be caused by an OS incompatability? The laptop is running Snow Leopard; the iMac (connected to the LaCie #1) is running Lion.

    No.  As long as the iMac is running 10.5.6 or later, it's fine.


    --Should I FORGET the whole plan to ever back up over the home network and just buy an inexpensive back up drive for the laptop so it has its own?


    I wouldn't.  It should work fine over your network (as it did in the past), and is much more convenient.  You're not likely to back up as often if you have to connect a drive periodically, and if you do that a lot, the plugs or ports can be damaged.


    However, it's always a good idea to keep an extra set of backups, as in the last paragraph of my previous post here.

  • Pondini Level 8 Level 8 (38,710 points)

    Leslie Goldberg wrote:

    . . .

    Bottom line is I am assuming that this problem was caused somehow by the sparsebundle on the LaCie getting corrupted or something.

    Yup.  Wireless backups are very convenient, but WIFI just isn't as reliable as old-fashioned wires.    Sometimes the backups get corruped, occasionally beyond repair.  Thus the recommendation to also make periodic backups to an external HD.


    Again, many thanks. I appreciate your patience and continued attention to this problem.

    You're quite welcome -- glad it's sorted out. 

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