rastacaliboy
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Q: how to restore a corrupt partition

Hello everybody!

 

I've had this problem for a while and posted it on multiples mac forum but nobody ever knew how to fix it.

Last year I tried to install window on my mac, but for some reason it didn't work and I am now stuck with a 100gb "untitled" partition. I am running out of space and I would really love to utilize these 100gb.

People told me to run bootcamp and to figure it out but when I run bootcamp, it says "The startup disk cannot be partitioned or restored to a single partition. The startup disk must be formatted as a single Mac OS Extended (Journaled) volume or already partitioned by Boot Camp Assistant for installing Windows." I have no idea what it means.

At this point I kinda gave up on installing windows (even if it would be nice), but all I want is get my 100gb back!

 

 

Thanks to anybody who can help!

 

Kevin

MacBook Pro with Retina display, OS X El Capitan (10.11.1)

Posted on Dec 30, 2015 7:35 AM

by Loner T,Solvedanswer
Loner T Loner T
Level 7 (23,898 points)
Safari
A:

If you do not want to install Windows, then the simplest and safest method to get your disk space back is

 

1. Backup OSX and all your files - Use Time Machine to back up or restore your Mac - Apple Support .

2. Boot into Internet Recovery (Command+Opt+R) - OS X: About OS X Recovery - Apple Support .

3. Click on Utilties -> Disk Utility and Erase your internal whole disk.

4. Restore OSX and your files - Use Time Machine to back up or restore your Mac - Apple Support .

 

This requires a separate external disk which can accommodate TM backup - Backup disks you can use with Time Machine - Apple Support .

Posted on Dec 30, 2015 10:15 AM

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rastacaliboy

Q: how to restore a corrupt partition

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  • Helpful answers

  • by Loner T,

    Loner T Loner T Dec 30, 2015 7:59 AM in response to rastacaliboy
    Level 7 (23,898 points)
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    Dec 30, 2015 7:59 AM in response to rastacaliboy

    Can you post the output of the following OS X Terminal commands?

     

    diskutil list

    diskutil cs list

    sudo gpt -vv -r show /dev/disk0

    sudo fdisk /dev/disk0

     

    The "sudo" commands will prompt for your password, and it will not be echoed back. You may also see a warning about improper use of "sudo" and potential data loss due to "abuse" of the command.

  • by rastacaliboy,

    rastacaliboy rastacaliboy Dec 30, 2015 8:37 AM in response to Loner T
    Level 1 (0 points)
    Dec 30, 2015 8:37 AM in response to Loner T

    Screen Shot 2015-12-30 at 4.36.07 PM.png

    thanks for your fast answer =)

  • by Loner T,

    Loner T Loner T Dec 30, 2015 8:42 AM in response to rastacaliboy
    Level 7 (23,898 points)
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    Dec 30, 2015 8:42 AM in response to rastacaliboy

    What year is your MBP?

  • by rastacaliboy,

    rastacaliboy rastacaliboy Dec 30, 2015 8:43 AM in response to Loner T
    Level 1 (0 points)
    Dec 30, 2015 8:43 AM in response to Loner T

    late 2013

  • by Loner T,

    Loner T Loner T Dec 30, 2015 9:05 AM in response to rastacaliboy
    Level 7 (23,898 points)
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    Dec 30, 2015 9:05 AM in response to rastacaliboy

    1. The BCA partitioning was executed when there was another external storage attached. This resulted in a Windows EFI being created.

    2. The disk0s4-disk0s7 should be merged into a single Free Space chunk.

    3. Run the following two procedures with all external storage disconnected.

         Resetting the System Management Controller (SMC) on your Mac - Apple Support

         How to Reset NVRAM on your Mac - Apple Support

    4. Your Mac supports EFI Boot and the BCA-created USB Installer can be re-used. Shutdown your Mac, connect the USB installer, power up the Mac and hold the Option key and select EFI Boot from USB and point the installer to the Free Space chunk created in step 2.

    5. Your USB installer should be on a USB Flash drive (preferably a USB2 flash drive).

  • by rastacaliboy,

    rastacaliboy rastacaliboy Dec 30, 2015 9:13 AM in response to Loner T
    Level 1 (0 points)
    Dec 30, 2015 9:13 AM in response to Loner T

    What do I have to do in 2.? I didn't get that/

    Then I have to reset SMC and NVRAM (not sure what it means but I can probably do it). but then I didn't get the part with the USB installer ?

     

    And the whole point of this is to recombine the 100gb to my main hard drive right?


    Sorry I'm not really good with macs

  • by Loner T,

    Loner T Loner T Dec 30, 2015 9:30 AM in response to rastacaliboy
    Level 7 (23,898 points)
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    Dec 30, 2015 9:30 AM in response to rastacaliboy

    Step 2 implies running the following in OSX Terminal.

     

    diskutil mergePartitions free Free disk0s4 disk0s7

     

    This will coalesce disk0s4-disk0s7 into a single Free Space chunk that EFI Boot can re-use. This will not go back to your OSX partition.

     

    Here is the help for syntax...

     

    diskutil mergePartitions

    Usage:  diskutil mergePartitions [force] format name

            DiskIdentifier|DeviceNode DiskIdentifier|DeviceNode

     

    Merge two or more pre-existing partitions into one.  The first disk parameter

    is the starting partition; the second disk parameter is the ending partition;

    this given range of two or more partitions will be merged into one.

     

    All partitions in the range, except for the first one, must be unmountable.

     

    All data on merged partitions other than the first will be lost; data on the

    first partition will be lost as well if the "force" argument is given.

     

    If "force" is not given, and the first partition has a resizable file system

    (e.g. JHFS+), it will be grown in a data-preserving manner, even if a different

    file system is specified (in fact, your file system and volume name parameters

    are both ignored in this case). If "force" is not given, and the first

    partition is not resizable, you will be prompted if you want to erase.

     

    If "force" is given, the first partition is always formatted. You should

    do this if you wish to reformat to a new file system type.

     

    Merged partitions are required to be ordered sequentially on disk.

    See diskutil list for the actual on-disk ordering; BSD slice identifiers

    may in certain circumstances not always be in numerical order but the

    top-to-bottom order given by diskutil list is always the on-disk order.

     

    Ownership of the affected disk is required.

     

    Example: diskutil mergePartitions JHFS+ NewName disk3s4 disk3s7

             This example will merge all partitions *BETWEEN* disk3s4 and disk3s7,

             preserving data on disk3s4 but destroying data on disk3s5, disk3s6,

             disk3s7 and any invisible free space partitions between those disks;

             disk3s4 will be grown to cover the full space if possible.

     

  • by rastacaliboy,Helpful

    rastacaliboy rastacaliboy Dec 30, 2015 10:12 AM in response to Loner T
    Level 1 (0 points)
    Dec 30, 2015 10:12 AM in response to Loner T

    OK i think i got step2. I still didnt get what i have to do for step 4 though. What s a usb installer ? Not sure what the deal is with that:(

    so if i got it right, this process will make me able to use the 100gb, but it will not be part of the "main" disk?

    Thanks

  • by Loner T,Helpful

    Loner T Loner T Dec 30, 2015 10:12 AM in response to rastacaliboy
    Level 7 (23,898 points)
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    Dec 30, 2015 10:12 AM in response to rastacaliboy

    The highlighted option takes a Windows ISO, and downloads the BC drivers and creates a Windows Installer. The creation of the USB Installer needs to executed only once. Once the USB Installer has been created, it can be used repeatedly.

     

    BootcampAssistant-Options.png

  • by rastacaliboy,

    rastacaliboy rastacaliboy Dec 30, 2015 10:11 AM in response to Loner T
    Level 1 (0 points)
    Dec 30, 2015 10:11 AM in response to Loner T

    Im having the hardest time understanding you haha !

    So the point of this whole process (1-4) is to install windows on the 100gb partition?
    Or is it to make that partition useable on my mac?

     

    What I ideally want to do is recombine the 100gb unusable partition to my main partition OSX.

    Thanks again for your help and your patience!

  • by Loner T,Solvedanswer

    Loner T Loner T Dec 30, 2015 10:15 AM in response to rastacaliboy
    Level 7 (23,898 points)
    Safari
    Dec 30, 2015 10:15 AM in response to rastacaliboy

    If you do not want to install Windows, then the simplest and safest method to get your disk space back is

     

    1. Backup OSX and all your files - Use Time Machine to back up or restore your Mac - Apple Support .

    2. Boot into Internet Recovery (Command+Opt+R) - OS X: About OS X Recovery - Apple Support .

    3. Click on Utilties -> Disk Utility and Erase your internal whole disk.

    4. Restore OSX and your files - Use Time Machine to back up or restore your Mac - Apple Support .

     

    This requires a separate external disk which can accommodate TM backup - Backup disks you can use with Time Machine - Apple Support .

  • by rastacaliboy,

    rastacaliboy rastacaliboy Dec 30, 2015 10:23 AM in response to Loner T
    Level 1 (0 points)
    Dec 30, 2015 10:23 AM in response to Loner T

    okay sounds good !!

     

    Thanks a lot for your help and happy holidays !!

  • by Loner T,

    Loner T Loner T Dec 30, 2015 10:49 AM in response to rastacaliboy
    Level 7 (23,898 points)
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    Dec 30, 2015 10:49 AM in response to rastacaliboy

    Please post back, if you run into any issues.

  • by Delila_mark,

    Delila_mark Delila_mark Mar 2, 2016 11:53 AM in response to rastacaliboy
    Level 1 (0 points)
    Mar 2, 2016 11:53 AM in response to rastacaliboy

    Hi, Yes! you can get back untitled partition using Bootcamp method. If you are not following the right procedure then it will cause even more waste situation. There is an application built for this purpose which will make easy your data recovery from an extended partition. http://robdawg.com/software-for-extension-partition-data-recovery-in-mac