Level 1

13 points

cannot launch gdisk on terminal

I have macbook pro OS X El Capitan and trying to launch gdisk on terminal but it gives me this error:

GPT fdisk (gdisk) version 1.0.1

Problem opening /dev/disk1 for reading! Error is 16.

I disabled the System Integrity Protection and checked it after booting and found it disabled. I'm using gdisk to overcome the partitioning problem "Windows detects GPT disk as MBR in EFI boot"

I also have another problem which is when I reboot my laptop after adding windows 10 by Boot Camp Assaistant I get this error unless I hit "alt" key, the error is:

"no bootable device. insert boot disk and press any key"

Any suggestions?

MacBook Pro, OS X El Capitan (10.11.5)

Posted on Jun 5, 2016 8:11 PM

20 replies

Loner T

Level 9

59,536 points

Jun 13, 2016 4:06 PM in response to fahad.

You need a space between "-l" (letter L) and "/dev/disk0".

fahad. Author

Level 1

13 points

Jun 13, 2016 4:15 PM in response to Loner T

I put a space and got the following output:

sudo gdisk -l /dev/disk0

GPT fdisk (gdisk) version 1.0.1

Warning: Devices opened with shared lock will not have their

partition table automatically reloaded!

Partition table scan:

MBR: hybrid

BSD: not present

APM: not present

GPT: present

Found valid GPT with hybrid MBR; using GPT.

Disk /dev/disk0: 625142448 sectors, 298.1 GiB

Logical sector size: 512 bytes

Disk identifier (GUID): 00006C5D-79C8-0000-316A-0000A9640000

Partition table holds up to 128 entries

First usable sector is 34, last usable sector is 625142414

Partitions will be aligned on 8-sector boundaries

Total free space is 262157 sectors (128.0 MiB)

Number Start (sector) End (sector) Size Code Name

1 40 409639 200.0 MiB EF00 EFI system partition

2 409640 449359719 214.1 GiB AF00 Macintosh HD

3 449359720 450629255 619.9 MiB AB00 Recovery HD

4 450629256 624880263 83.1 GiB 0700 Windows_NTFS_Untitl...

Loner T

Level 9

59,536 points

Jun 13, 2016 6:40 PM in response to fahad.

GDisk is fine as the output shows. Before you make changes, what year/model is your Mac?

fahad. Author

Level 1

13 points

Jun 13, 2016 6:50 PM in response to Loner T

I'm sorry but I didn't get your question. Is the following the answer to your question? MacBook Pro Early 2011OS X El Capitan 10.11.5

IF not, please explain what do you mean by your question.

Thanks.

Loner T

Level 9

59,536 points

Jun 13, 2016 7:38 PM in response to fahad.

The reason for asking that question is that your specific model from 2011 only supports a BIOS/MBR installation, and will have issues if you remove the MBR. Your Mac also requires a physical DVD to install Windows 7/8.1. W10 is not officially supported on the 2011 models.

The only path to get W10 on your model, is to upgrade from W7/W8.1 to W10 using in-place upgrade.

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cannot launch gdisk on terminal