Q: How to I fix my Mac startup drive

agun21st wrote:

I am here now... what should Next?

Say 'N here. You do not want to use README.windows as device name. You want to enter "0:" without the quotes (that is the digit zero and ':'). Press 'p' to print the GPT.

You can use http://windows.microsoft.com/en-us/windows7/products/features/snipping-tool to take screen shots and post. Using a camera is a bit more tedious.

sir here is the screen shot...

My Device Manager Screen Shot sir.

Please find a USB2 of 16+ GB. Use Command+Opt+R (Internet Recovery), install OS X on this USB drive. Install GPT Fdisk on this USB after you boot from it, and boot from this USB.

Please post the output of

sudo gpt /dev/disk0

Quick reply need sir. I am in a Cyber Cafe for Internet Connection.

Sir Finally by (Internet Recovery) I installed OS X Yosemite 10.10 in a 32GB USB Flash Drive and boot from it now. here is some Terminal logs.

When Boot from USB Flash Drive OS X Yosemite 10.10 show this warning first. Then I pressed "Ignore"

I used Terminal and do this for present Logs.....

Last login: Sat May  2 10:52:03 on ttys000

Mahadis-MacBook-Pro:~ Mahadi_Hassan_Razib$ sudo gpt /dev/disk0

Password:

gpt: unknown command: /dev/disk0

Mahadis-MacBook-Pro:~ Mahadi_Hassan_Razib$ gpt /dev/disk0

gpt: unknown command: /dev/disk0

Mahadis-MacBook-Pro:~ Mahadi_Hassan_Razib$ diskutil list

/dev/disk0

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:     FDisk_partition_scheme                        *751.3 GB   disk0

   1:                Windows_LDM                         521.3 GB   disk0s1

   2:                Windows_LDM                         230.0 GB   disk0s2

   3:                Windows_LDM                         1.6 MB     disk0s3

/dev/disk1

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *30.9 GB    disk1

   1:                        EFI EFI                     209.7 MB   disk1s1

   2:                  Apple_HFS Macintosh HD USB        30.1 GB    disk1s2

   3:                 Apple_Boot Recovery HD             650.0 MB   disk1s3

Mahadis-MacBook-Pro:~ Mahadi_Hassan_Razib$ diskutil cs list

No CoreStorage logical volume groups found

Mahadis-MacBook-Pro:~ Mahadi_Hassan_Razib$ sudo gpt -vv -r show /dev/disk0

Password:

gpt show: /dev/disk0: mediasize=751277983744; sectorsize=512; blocks=1467339812

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  1018122239      1  MBR part 66

  1018122240   449212416      2  MBR part 66

  1467334656        3108      3  MBR part 66

  1467337764        2048      

Mahadis-MacBook-Pro:~ Mahadi_Hassan_Razib$ sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 91337/255/63 [1467339812 sectors]

Signature: 0xAA55

         Starting       Ending

#: id  cyl  hd sec -  cyl  hd sec [     start -       size]

------------------------------------------------------------------------

1: 42    0   0   2 - 1023 254  63 [         1 - 1018122239] LinuxSwap DR

*2: 42 1023 254  63 - 1023 254  63 [1018122240 -  449212416] LinuxSwap DR

3: 42 1023 254  63 - 1023 254  63 [1467334656 -       3108] LinuxSwap DR

4: 00    0   0   0 -    0   0   0 [         0 -          0] unused   

Mahadis-MacBook-Pro:~ Mahadi_Hassan_Razib$

And Finally I Installed also GPT Fdisk gdisk-1.0.0.pkg (after installed disk-1.0.0.pkg does not my restart MacBook pro)

Waiting for your Reply sir

After you installed GPT Fdisk, it does not restart your Mac. If you notice, there is an error message

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

This indicates that GPT is unable to properly read data. GPT Fdisk (also known as gdisk) will correct the CRC error and allow us to see the GPT. It can also read the backup GPT table.

Can you post the output of

sudo gdisk /dev/disk0

gdisk is normally installed in /usr/sbin/ . There is also a second utility called cgdisk, which has a character-based graphical interface.

$ type gdisk

gdisk is /usr/sbin/gdisk

$ type cgdisk

cgdisk is /usr/sbin/cgdisk

Let us use gdisk for now. Please be aware that you are also posting your name in some cases. Do you want it to be removed from you posts?

Sir,

After you installed GPT Fdisk, there was no error message.

Output of

sudo gdisk /dev/disk0

Last login: Sun May  3 05:25:02 on console

Mahadis-MacBook-Pro:~ Mahadi_Hassan_Razib$ sudo gdisk /dev/disk0

Password:

GPT fdisk (gdisk) version 1.0.0

Caution: invalid backup GPT header, but valid main header; regenerating

backup header from main header.

Caution! After loading partitions, the CRC doesn't check out!

Warning! Main and backup partition tables differ! Use the 'c' and 'e' options

on the recovery & transformation menu to examine the two tables.

Warning! One or more CRCs don't match. You should repair the disk!

Partition table scan:

  MBR: MBR only

  BSD: not present

  APM: not present

  GPT: damaged

Found valid MBR and corrupt GPT. Which do you want to use? (Using the

GPT MAY permit recovery of GPT data.)

1 - MBR

2 - GPT

3 - Create blank GPT

Your answer:

and YES sir, if it will create problem then remove my name from post.

this is the present condition of command. My Answer Should be what?

Found valid MBR and corrupt GPT. Which do you want to use? (Using the

GPT MAY permit recovery of GPT data.)

1 - MBR

2 - GPT

3 - Create blank GPT

 

Your answer: 2

You should answer 2. The goal is to recover the GPT. Run the following commands once you are in gdisk, but do not use the 'w' command.

p

r

e

y

p

o

Sir I did. here is logs.

now should do what sir?????

This is confusing. Did you answer 'p' or '2'?

You will also need to d, 17 and d, 19. The remaining entries (1-4) look correct.

Sir I did according to your instructions. and I used p not 2. I edited my last picture and indicate by red Line.

In Gdisk main menu, please delete entries 17 and 19. Please post the output after you delete the two entries.

sudo gpt -vv -r show /dev/disk0

cydget wrote:

 

Will setting the mac partition to Apple boot(ab00) or to Apple HFS/HFS+(af00) fix the problem?

The Macintosh HD 2 partition is windows. Just so you dont get confused.

OS X only looks at the GPT for EFI boot information, which is confusing OS X. It should be AF00 or AF05 depending on if it is HFS+ or CS. You should also change the Recovery HD to AB00. In Gdisk, can you check the following (do not use 'o' in the main Gdisk menu which will cause worse problems).

Command (? for help): r

 

Recovery/transformation command (? for help): o

 

Disk size is 500118192 sectors (238.5 GiB)

MBR disk identifier: 0xAE6E4269

MBR partitions:

 

Number  Boot  Start Sector   End Sector   Status      Code

   1                     1       409639   primary     0xEE

   2                409640    250801735   primary     0xAC

   3             250801736    252071271   primary     0xAB

   4      *      252071936    500117503   primary     0x07

Sir I am extremely sorry for my mistake. now I use my Answer is (2) see the picture below.

after I use your command and attached picture.

sudo gpt -vv -r show /dev/disk0

But I don't understand how to do this ?

In Gdisk main menu, please delete entries 17 and 19. Please post the output after you delete the two entries.

waiting for you reply sir. please...