m0ng

Q: Partition pain

I was trying to free up some space from my windows 10 partition to go back to my Mac OS X 10.10.2 partition. You used to be able to do this in either boot amp or the disk utility just by dragging the sliders, I'm sure...i couldn't get it to work in Mac I looked online and read somewhere that Windows 10 could do it natively.

 

In Windows 10 disk management o resized the bootcamp partition to free up some space. This then created an empty partition, so I headed back to OS X, but it didn't seem to see it in disk utility, aback to Windows 10, I thought if I formatted it as fat32 os X would see it and be able to reclaim the space.

 

That's when the sh*t hit the fan:

 

-cant boot into os X

-cant boot into Windows 10

 

when booting the screen is black for a long time then the machine tries to book Windows but says there's no bootable media (or something similar).

 

I tries command + R to load online help/utilities but disk utility their recognises all the partitions but cannot seem to do anything with them, like delete or repair etc. It says it can't make changes to the boot map (apologies not exact mssage(s) have subsequntly been drinking to numb the misery of it. Am away from home, so don't have any bootable media Or any backups with me.

 

basically I've broken the guild map I think but because everything's greyed out in the utilises, I can't erase any partitions (if that's what I need to do).

 

would someone please give me some advice? - will it be possible to save the data on the os X partition? (Not so bothers about Windows 10)???

 

thanks in advance

 

david

 

Macbook pro retina 15inch 2012

Posted on Dec 28, 2015 9:10 PM

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Q: Partition pain

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  • by Loner T,

    Loner T Loner T Dec 31, 2015 5:26 PM in response to m0ng
    Level 7 (24,611 points)
    Safari
    Dec 31, 2015 5:26 PM in response to m0ng

    Command (? for help): r

     

    Recovery/transformation command (? for help): ?

    b use backup GPT header (rebuilding main)

    c load backup partition table from disk (rebuilding main)

    d use main GPT header (rebuilding backup)

    e load main partition table from disk (rebuilding backup)

    f load MBR and build fresh GPT from it

    g convert GPT into MBR and exit

    h make hybrid MBR

    i show detailed information on a partition

    l load partition data from a backup file

    m return to main menu

    o print protective MBR data

    p print the partition table

    q quit without saving changes

    t transform BSD disklabel partition

    v verify disk

    w write table to disk and exit

    x extra functionality (experts only)

    ? print this menu

  • by m0ng,

    m0ng m0ng Dec 31, 2015 5:30 PM in response to Loner T
    Level 1 (62 points)
    iPhone
    Dec 31, 2015 5:30 PM in response to Loner T

    Sorry, how do you get to that menu, the one with the recovery/transformation options?

     

    I really should just read.*slaps self*

  • by m0ng,

    m0ng m0ng Dec 31, 2015 5:32 PM in response to Loner T
    Level 1 (62 points)
    iPhone
    Dec 31, 2015 5:32 PM in response to Loner T

    I pressed f and then y to confirm the action.

  • by Loner T,

    Loner T Loner T Dec 31, 2015 5:40 PM in response to m0ng
    Level 7 (24,611 points)
    Safari
    Dec 31, 2015 5:40 PM in response to m0ng

    Can you post the output of the GPT command? Let us check what it looks like.

  • by m0ng,

    m0ng m0ng Dec 31, 2015 5:45 PM in response to Loner T
    Level 1 (62 points)
    iPhone
    Dec 31, 2015 5:45 PM in response to Loner T

    hopefully i've got it right and it's this one:

     

    Last login: Fri Jan  1 01:41:25 on ttys000

    davids-MacBook-Pro:~ m0ng$ sudo gpt -vv -r show /dev/disk0

    gpt show: /dev/disk0: mediasize=500277790720; sectorsize=512; blocks=977105060

    gpt show: /dev/disk0: MBR at sector 0

    gpt show: /dev/disk0: Bad CRC in GPT table at sector 2

          start       size  index  contents

              0          1         MBR

              1  703668223      1  MBR part 66

      703668224  210522112      2  MBR part 66

      914190336   62912676      3  MBR part 66

      977103012       2048        

    davids-MacBook-Pro:~ m0ng$

     

    I noticed some remain commands from the recovery section, one was to write the changes to disk and exit...im afraid i didn't do that, as you didn't say...was that a mistake?

  • by Loner T,

    Loner T Loner T Dec 31, 2015 5:55 PM in response to m0ng
    Level 7 (24,611 points)
    Safari
    Dec 31, 2015 5:55 PM in response to m0ng

    After you run

     

    r

    f

    p

    w

    y

     

    Run the GPT command again.

  • by m0ng,

    m0ng m0ng Dec 31, 2015 6:04 PM in response to Loner T
    Level 1 (62 points)
    iPhone
    Dec 31, 2015 6:04 PM in response to Loner T

    got this again after w not sure if it's important:

     

    Warning! Main partition table overlaps the first partition by 33 blocks!

    You will need to delete this partition or resize it in another utility.

    Aborting write of new partition table.

     

    Last login: Fri Jan  1 02:01:55 on ttys000

    davids-MacBook-Pro:~ m0ng$ sudo gpt -vv -r show /dev/disk0

    gpt show: /dev/disk0: mediasize=500277790720; sectorsize=512; blocks=977105060

    gpt show: /dev/disk0: MBR at sector 0

    gpt show: /dev/disk0: Bad CRC in GPT table at sector 2

          start       size  index  contents

              0          1         MBR

              1  703668223      1  MBR part 66

      703668224  210522112      2  MBR part 66

      914190336   62912676      3  MBR part 66

      977103012       2048        

     

    I know it's not usually recommended, but if you have the means, and it is easier for you, I would let you remote control...

  • by Loner T,

    Loner T Loner T Dec 31, 2015 6:20 PM in response to m0ng
    Level 7 (24,611 points)
    Safari
    Dec 31, 2015 6:20 PM in response to m0ng

    m0ng wrote:

     

    Sorry. Hope I'm not making you rip your hair out.

     

    btw ever now and again I'm getting an error come up in OS X saying "the disk inserted is unreadable by os x" or something similar...

     

    anyway:

     

    003.jpg

    Create a blank new GPT, and create new entries using these start/end values. You need to use the n command and maintain the sequence and code column.

  • by m0ng,

    m0ng m0ng Dec 31, 2015 6:42 PM in response to Loner T
    Level 1 (62 points)
    iPhone
    Dec 31, 2015 6:42 PM in response to Loner T

    i seem to be having problems with 17 - it keeps asking for the first sector and i keep typing it, and it just keeps asking again...any ideas?

     

    ommand (? for help): n

    Partition number (5-128, default 5): 17

    First sector (34-977105026, default = 34) or {+-}size{KMGTP}: 18376656804508598272

    First sector (34-977105026, default = 34) or {+-}size{KMGTP}: 4613656343264362496

    First sector (34-977105026, default = 34) or {+-}size{KMGTP}: 18376656804508598272

    First sector (34-977105026, default = 34) or {+-}size{KMGTP}: 18376656804508598272

    First sector (34-977105026, default = 34) or {+-}size{KMGTP}: ?             

    First sector (34-977105026, default = 34) or {+-}size{KMGTP}:

     

    you can see the 2nd entry i didn't look and carried on writing the end sector value.

  • by m0ng,

    m0ng m0ng Dec 31, 2015 6:49 PM in response to m0ng
    Level 1 (62 points)
    iPhone
    Dec 31, 2015 6:49 PM in response to m0ng

    The values are bigger than the guidelines..that must be the problem but ....I have no idea how to continue.

  • by Loner T,

    Loner T Loner T Dec 31, 2015 7:55 PM in response to m0ng
    Level 7 (24,611 points)
    Safari
    Dec 31, 2015 7:55 PM in response to m0ng

    You need only 1-4. We tried a delete which was not being wriiten. 

  • by m0ng,

    m0ng m0ng Dec 31, 2015 7:58 PM in response to Loner T
    Level 1 (62 points)
    iPhone
    Dec 31, 2015 7:58 PM in response to Loner T

    So i don't think what i did actually finished/wrote itself to disk. So i'll do it again and then what sort of percentage to finished are we do you think?

  • by Loner T,

    Loner T Loner T Dec 31, 2015 8:02 PM in response to m0ng
    Level 7 (24,611 points)
    Safari
    Dec 31, 2015 8:02 PM in response to m0ng

    If the GPT is correct, we need to test booting.

  • by m0ng,

    m0ng m0ng Dec 31, 2015 8:25 PM in response to Loner T
    Level 1 (62 points)
    iPhone
    Dec 31, 2015 8:25 PM in response to Loner T

    K. These are the issues now:

     

    1. The bootcamp drive now appears in finder and the files therein seem to be as was (i haven't tried booting into windows, see 3.)

    2. The mac hd partition is a different story, see pic, greyed out.

    3. When i press option during bootup no drives other than the SD card that this os x el cap is installed on appear.

     

    disk util.jpg

  • by Loner T,

    Loner T Loner T Dec 31, 2015 8:55 PM in response to m0ng
    Level 7 (24,611 points)
    Safari
    Dec 31, 2015 8:55 PM in response to m0ng

    Can you post the output of the GPT command? 

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