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Thread: Partitions have vanished

  1. #11
    Join Date
    Sep 2011
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    46

    Re: Partitions have vanished

    Quote Originally Posted by oldfred View Post
    The first sector of a partition is like the first sector of a drive in that it has boot info. For NTFS partitions it must match the partition table and have a valid NTFS signature. So moving the start of a NTFS partition will definitely create problems.

    But do not know what the end of sda should be. You might try looking in testdisk as it finds old partitions, but it reports the info in the old cylinders, heads, sectors and it is not easy to relate. But if you want to see what it says:

    Testdisk uses CHS - formula for conversion to LBA
    http://en.wikipedia.org/wiki/Cylinder-head-sector
    I'm sorry, I don't understand what you're talking about. Isn't sda the whole drive? Or do you mean sda1?

    If you mean sda1, I think (according to what I have been reading lately) that I can find out what the end position should be by just adding the size of the partition to the start position (that makes sense for me). If I do like this, however, it seems to be a large gap between sda1 and sda2, so I don't know if it is wrong or right.

    About testdisk, what for should I use it? To recover the partition table or just to get info?

    Thanks.

  2. #12
    Join Date
    Jun 2009
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    Chicago Suburbs
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    Hidden!
    Distro
    Ubuntu 14.04 Trusty Tahr

    Re: Partitions have vanished

    Yes, I meant sda1.

    I would use testdisk to see if it shows a sda1 that does not overlap sda2. It it does and looks reasonable then I would see if it would update. But save the current partition info, so you could revert and manually do it if necessary.

    Backup partition table to text file & save to external device.
    sudo sfdisk -d /dev/sda > PTsda.txt
    For info on UEFI boot install & repair - Updated Mar 2015:
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to close thread when/if answered completely.







  3. #13
    Join Date
    Sep 2011
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    46

    Re: Partitions have vanished

    I think I'm just gonna use sfdisk to shrink sda1 and the gparted to get rid of windows. ¿Any warning i should keep on mind while doing it?

    And, by the way: ¿will it be any problem if, using gParted, I erase a bootable partition? I so, ¿what if I do it from a Pangolin live cd and then I use it to install PP in a new partition? ¿Will it automatically become bootable?

    Thanks everyone, you're being really helpful.

  4. #14
    Join Date
    May 2008
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    United Kingdom
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    4,270
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    Ubuntu 12.04 Precise Pangolin

    Re: Partitions have vanished

    If you delete the bootable partition, that's not a problem, as Ubuntu will fix it when you install.

    However, if you are keeping Windows, that may cause a problem particularly if you need to restore Windows -- Windows tends to use hidden partitions to store restoration data.
    Problems with WINE?
    Full Circle Magazine :: Confused "allot"? :: Cheap Linux stickers
    In my day, we had outdoors in which to run, play, and socialise. Now we have computers to do those.

  5. #15
    Join Date
    Sep 2011
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    Re: Partitions have vanished

    It's not a big deal if I lose Win7, but I'd like to keep it... ¿will it crash even if I just shrink his hidden partition?

  6. #16
    Join Date
    May 2008
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    Ubuntu 12.04 Precise Pangolin

    Re: Partitions have vanished

    Messing with Windows's partitions is tricky. You do so at the risk of losing Windows.

    Windows is terribly fussy.

    Here is what I suggest:


    1. Reinstall Windows. Warning: This will delete all data on your disk, probably including your Ubuntu data, so be sure to back up all your data first.
    2. Use Windows tools (from your Administration menu) to shrink the main Windows partition to the size you want. It is safer to shrink your Windows partitions using Windows tools rather than Linux tools. This will leave spare, unused space on your hard drive.
    3. Finally, install Ubuntu in the spare space that is left on your drive.


    You do not have to do it that way. But in any case, please back up all your data first, in case of any problems.
    Problems with WINE?
    Full Circle Magazine :: Confused "allot"? :: Cheap Linux stickers
    In my day, we had outdoors in which to run, play, and socialise. Now we have computers to do those.

  7. #17
    Join Date
    Sep 2011
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    46

    Re: Partitions have vanished

    Well, I've finally fixed it!

    At the end I've just edited the Partition Table to shrink sda1 with sfdisk (I've never been more frightened!) and then I just got rid of my ubuntu partition and I've created a new extended one, where I've installed Pangolin from scratch (it's currently being installed, in fact).

    So it seems everything is gonna be ok

    I cannot thank you all enough for such a kind and useful help. Thanks everyone!


    PD: it seems I've lost sda1, or at least Windows Recovery is no going to work anymore, but I really don't mind, I think I will make it a extended partition and use it to try other OS
    Last edited by Carllacan; May 5th, 2012 at 01:18 AM.

  8. #18
    Join Date
    May 2008
    Location
    United Kingdom
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    4,270
    Distro
    Ubuntu 12.04 Precise Pangolin

    Re: Partitions have vanished

    I'm glad you managed to resolve this. It was a bit of a confusing problem.

    Please mark the thread as solved.
    Problems with WINE?
    Full Circle Magazine :: Confused "allot"? :: Cheap Linux stickers
    In my day, we had outdoors in which to run, play, and socialise. Now we have computers to do those.

  9. #19
    Join Date
    Sep 2011
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    46

    Re: Partitions have vanished

    For eveyone coming here with alike problems: Olfred's answer was very very helpful:

    Quote Originally Posted by oldfred View Post
    Overlapping partitions is one reason gparted will not show a drive as the corruption creates issues it cannot resolve.

    Run this as what you have posted does not necessarily show overlap. This shows more detail by sectors.

    Code:
    sudo fdisk -lu
    You should also backup partition table just in case.

    Backup partition table to text file & save to external device.
    sudo sfdisk -d /dev/sda > PTsda.txt

    Fix overlaping partition error srs5694 post #34
    http://ubuntuforums.org/showthread.php?t=1667614
    http://www.rodsbooks.com/missing-parts/index.html

    But you may just have to use sfdisk. The issue is, if partitions overlap which partition does the overlap belong to and does it contain any data from one, or the other, or both and is corrupted?
    Using sfdisk to fix partition table problems - not without risk
    http://ubuntuforums.org/showthread.php?t=1192598

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