Can't format external drive to Mac OS Extended (Journaled)

Discussion in 'Mac Basics and Help' started by steinramm, Jul 8, 2009.

  1. steinramm macrumors member

    Aug 16, 2007

    I have the external drive formated as FAT of 1TB.

    I have erasing all data whole day (about 20 hours) and formating as Mac OS Extended (Journaled) but at the end it reports an error.

    Now, when I connect hard drive to my MBP it says "disk is not readable on this computer" - Initialize...

    When i try to format as Mac OS Extended (J) it says: "Disk erase failed with error: File system formated fail"

    I tried to format it on PC (Vista and XP) but they even can't see hard disk.

    What should I do to get journaled formated external hard drive?

    Thanks in advance!
  2. surflordca macrumors 6502a


    Nov 16, 2007
    Ontario, Canada
    How are you trying to format your HDD? From the "Disk Utility" icon highlite the disk you want to format. Not any disks inside the main disk. You have to select the mail disk you want to format...
  3. steinramm thread starter macrumors member

    Aug 16, 2007
    Hi, yes, from Disk Utility and I'm selecting main drive, not the one inside.
  4. -tWv- macrumors 68000


    May 11, 2009
    I had the same problem. I bought a WD My Book 1TB hard drive and there was a problem with it formatting. I wanted to use this disk for time machine as well as partition it so i had some miscellaneous storage space. This was my solution

    Try formatting the disk to FAT, this worked fine for me, at least now it can be seen and read by both windows and osx. Then I went into time machine and selected "change disk". It then prompted me and said that it had to erase the entire drive and reformat. The reformatting with time machine worked fine and the drive was then in mac format. After it does that it starts to backup your drive, you can just cancel this and use the drive how you want. Or if you want to use it with time machine then let it do the initial backup. Make sure you always have a drive with a time machine backup of your computer on it because if somehow you mess up your disk, you are screwed if you didn't back up.
  5. madog macrumors 65816


    Nov 25, 2004
    Korova Milkbar
    You have to change the drive from Master Boot Record to GUID (Intel) or Apple Partition (PPC). Pretty much all drives not purchased at an Apple store will be MBR with a FAT format allowing it to work on both OS X and Windows, but MBR can't be formatted to HFS+ (Mac OS Extended) specifically for Macs. However, GUID works with HFS+ and FAT/NTFS partitions, as seen with BootCamp. Although, that might just be a Mac specific thing, and if you want true cross compatibility it may need to be MBR/FAT.


    Disk Utility
    Select Drive from left
    Click Partition Tab
    Select 1 partition from pull down menu (or whatver you want, though this must be changed from "Current")
    Click Options button
    Select your Partition Table, click OK
    Change format to what you want
    Name your partition
    Hop on one leg
    Dance in a circle!
    Click Apply

    Same deal if you want to store a 4GB+ file on a flash drive. They are all MBR/FAT and can't store such large files, so if you use a Mac you can format it to GUID/HFS for the transfer, and then can change it back with Disk Utility to MBR/FAT for normal use.
  6. -tWv- macrumors 68000


    May 11, 2009
    Oh thanks, i guess the time machine formatting changes the drive to GUID and formats it. That's why it works. Thanks for clearing that up

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