Lost Partitions

Discussion in 'Windows 7 Help and Support' started by UKAspie, Feb 8, 2010.

  1. UKAspie

    UKAspie Honorable Member

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    I installed W-XP on a PATA drive, then 'upgraded' to W-7 on a SATA drive. Unfortunately it seems to have installed part of W-7 on the PATA drive so I can't remove it. I adjusted the partitions on the PATA and all partitions on the SATA apart from the first vanished. They are visible in "Disk Management" but when I try to access one it says:
    "The operation failed to complete because the Disk Management console view is not up-to-date ..." Rebooting does not help. Can someone recommend a recovery utility?
     
  2. Saltgrass

    Saltgrass Excellent Member
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    What happened is the boot files for Win 7 were put on the active XP partition.

    Can you tell if the Win 7 partition is marked active, or can you mark it active in Disk Management?

    When partitions disappear, they probably no longer have drive letters. You can add those by right clicking and add. Right clicking is also how you set it to active. You can only set one partition at a time per drive to active.

    You can use disk management from either XP or Win 7.

    Once you have the Win 7 partition marked as active, disconnect the PATA drive, boot to the Win 7 install DVD (or repair CD) and go to the second window and look for the repair option on the lower left. Choose that and run a startup repair 2 or 3 times.

    So you will know, the system will boot to the first active partition on the hard drive listed first in the bios under drive order (or something similar).

    If something doesn't work correctly, reconnect the PATA drive and during boot go into the bios and set that drive as first. You will then be able to boot back to the PATA drive.
     
  3. UKAspie

    UKAspie Honorable Member

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    Thanks. The repair option might work, I took it as far as selecting repair and it asked for the driver "media" to be loaded. I couldn't install to the SATA drive because at install time it insisted on the driver "floppy" and I don't have a floppy drive on this MB. If I burn the SATA drivers to the root of a CD should that work?

    <<When partitions disappear, they probably no longer have drive letters.>>
    True.

    <<You can add those by right clicking and add.>>
    That's how I got the error message I quoted above. I have rebooted and tried again - that doesn't help.

    To muddy the waters even more, the missing partitions are present and correct in XP. I think the XP Disk Manager has "corrected" the partition table so it is not readable by W7. I think I am now asking a more difficult question: in what way are XP and W7 partition tables incompatible? I am prepared to use a hex editor on the partition table if I know what is different about W7. It's a "Basic" disk, i.e. not Microsoft proprietary partition format.
     
  4. Saltgrass

    Saltgrass Excellent Member
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    This muddies the water because it sounds like you want to get rid of the PATA drive.

    I have never used a partition recovery utility, but you can check the net for one.

    If you attach a snipping tool picture of your disk management window, it might help, but it sounds like the partition resizing did not go well, or disk management is having a problem. It may take a long time to adjust partition sizes.

    If you want a partition management utility, you might try this one, but I do not know if it will recover a partition. You could, however, boot to it to get a more accurate picture of what is going on.
     
  5. UKAspie

    UKAspie Honorable Member

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    Solution found

    A bit slow to reply, but I have sorted the partitions. I used a hex editor and corrected the partition table by hand. Not recommended unless you really know what should be there.

    Partition table entries specify the partition by its start and end sector in C:H:S format. As this is a 24 bit field it can only go up to 8 GB. On a disk larger than 8 GB (i.e. all disks these days) the partition is specified by its starting sector number and number of sectors and the C:H:S values are set to 0xFFFFFE. One of the utilities I used, which might actually have been Yast, "corrected" the table by calculating C:H:S values from the physical sector numbers and writing them in - modulo 8 GB.

    Interestingly, Windows XP correctly ignored the C:H:S values because the disk was larger than 8 GB, but Windows 7 attempted to use them. This implies that W-7 uses some code that is older than XP.
     

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