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  1. #1


    Member Since
    Mar 05, 2010
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    5
    External Hard Drive can't boot!
    I have a Seagate 500GB external hard drive that was formatted on my Macbook at FAT32. I was using it without problem both on my Macbook and my brother's Windows 98 desktop. I tried to use in with my new laptop, running Windows 7. I found out I had to assign a volume letter to it in order to see its contents. I did so, only to get a message asking me to format the drive! Moreover, now I cannot use it neither on my Macbook nor at my brother's desktop... I tried removing the letter but nothing changed; it is still unrecognizable, telling me that no known operating system is installed in it (or something like that)... I guess it's a disk header thing (after assigning a volume letter). Maybe I could fix this with some kind of software?
    Any help would be greatly appreciated!
    Dionysis.

  2. #2

    chscag's Avatar
    Member Since
    Jan 23, 2008
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    Fort Worth, Texas
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    Specs:
    Late 2013 27" iMac, iPad 3, iPhone 6s+, iPhone 6+, 3 iPods, El Capitan
    When you allowed Windows 7 to format the drive, it automatically defaulted to using NTFS since Windows will not format any drive over 32 GB to other file formats.

    Your brother's Win98 can neither read nor write to NTFS. Win98 can only read and write FAT and FAT-32. Your MacBook should be able to read from the drive but not write to it. Of course formatting wiped everything on the drive out, so that may be the reason your MacBook sees nothing.

  3. #3


    Member Since
    Mar 05, 2010
    Posts
    5
    I didn't format the drive!
    I just assigned a volume letter to it, because otherwise I could not see its contents in Windows 7.

  4. #4

    chscag's Avatar
    Member Since
    Jan 23, 2008
    Location
    Fort Worth, Texas
    Posts
    49,094
    Specs:
    Late 2013 27" iMac, iPad 3, iPhone 6s+, iPhone 6+, 3 iPods, El Capitan
    First of all, I don't know why you had to assign a drive letter to an external drive in order to "see" it in Windows 7? The drive should have mounted automatically and been assigned the next available drive letter. So that tells me something was wrong with the drive.

    If you originally formatted that drive to FAT-32 using Disk Utility from your Mac, it may have been formatted using the GUID scheme instead of MBR.
    That will mess over a drive because it places an EFI hidden partition on it consisting of 200MB. That may be why Windows 7 needed to assign a drive letter to it.

    Anyway, I'm not sure what you did... but it appears your drive is unusable.

    You can try fixing it by following these instructions: LINK Note: After doing this, you'll need to partition and format the drive again. If you use Disk Utility, make sure you specify the MBR partition scheme otherwise you'll have the same problem again.

  5. #5


    Member Since
    Mar 05, 2010
    Posts
    5
    Many thanks for your filling-in!
    Hm... I guess it must have been the MBR thing. Makes sense.
    I'll try a file recovery program to get to the files before re-formatting the disk...
    Hope it works!

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