Fixing MBR

Discussion in 'Acronis Disk Director Suite' started by Howard Kaikow, Jul 27, 2009.

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  1. Howard Kaikow

    Howard Kaikow Registered Member

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    Can ADD fix an MBR?
    And keep the partition table?

    I ran a script in Ubuntu tonight.

    It showed that I have Grub0.97 on my ZIP disk, and on my I drive.

    Do not know how they got there, likely 2+ years ago when I was messing around installing Ubuntu 7.04.

    And, I've got GAG in the MBR of my C drive.
    Again, that likely happened 2+ years ago.

    I got rid of the one on the ZIP drive by copying the files to new media.

    I've heard that there are programs for restoring an MBR, such as MBRFix. Which such programs are recommended? Or can I do this with ADD?

    To what state do they restore the MBR?
    Do they wipe out the partitions, or leave the partiton tables intact?

    I did not install Ubuntu 9.04 to an MBR.
    2+ years ago, I may have inadvertently done so.
     
  2. K0LO

    K0LO Registered Member

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    Howard:

    By "fixing" an MBR, I am assuming that you mean that you'd like to replace the boot loader code with the standard Microsoft MBR. The easiest way to do that is to use an XP or Vista recovery disk and execute a fixmbr command (XP) or bootrec /FixMbr (Vista). Each of these tools replaces only the boot loader code in the MBR without affecting the partition table.

    GRUB, when installed to the MBR, uses more than just the first sector on the disk for its code (I think it uses the first 16 sectors, although I am not positive). Although not necessary, if you want to remove all traces of GRUB from the machine then you could use the disk editor in ADD to also write zeros to any of the other sectors in the first track that contain code. In other words, zero sectors 2 through 16, leaving the first sector with the MBR untouched.

    If you're a Linux guy then of course you can also do this with the Linux command dd.

    ADD can be used to back up and restore the MBR. Just save a copy of the first sector on the disk to a file. Be careful when restoring this copy because the first sector also contains the partition table. If you make any changes to the disk partition layout and then restore an old saved copy of the first sector, you will replace the partition table with an old copy. Thus, you risk losing data. But if you're careful and think about what you're doing, then having a copy of the first sector may be useful as a backup.
     
  3. Howard Kaikow

    Howard Kaikow Registered Member

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    Alas, I do not have the recovy console installed.
    I'll try a recovery disk.

    I looked at the Disk Editor.
    I'm not courageous enough to edit those sectors.

    I'm not courageous enough to edit those sectors.

    As I recall, the first 446 bytes are safe to copy and restore.
    But I do not have the courage.
     
  4. K0LO

    K0LO Registered Member

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    A great way to learn is to practice on a spare hard disk. Restore an image of one of your PCs to the spare disk and practice away. Make a few mistakes, screw up the ability to boot a few times and then practice fixing things with TI and ADD. This will help you keep a cool head when disaster strikes for real.
     
  5. Howard Kaikow

    Howard Kaikow Registered Member

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    It is not cost effective, for me, to do disk editing.
    I maintain image backups, and would update them before I modify the MBR on any drive.

    I got rid of the grub0.97 on the ZIP disk by copying the files to a new ZIP disk.
    I got rid of Gag in the MBR on the drive that has C by using the Windows recovery console. It remains a mystery as to how Gag got there.

    I still need to get rid of grub0.97 on the drive that has I-M, with an OS on J.
    But the recovery console referred to partitions K, L , and M, where thay are actully F,G, and J. I guess that I could have asked recovery console to do all 3, but I felt unfortable due to the odd drive letters.

    There is a Windows version of TestDisk. I can boot to an OS on drive 2, and change the MBR on drive 3. But, I need to verify whether the partition table will be left intact.

    Another possibility may be to build an Ultimate Boot CD for Windows. It has TestDisk, but might also have fixmbr. I need to build an UBCD anyway, might as well do it sooner than later.
     
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