User profile for user: Hikarikaze
Hikarikaze Author
User level: Level 1
4 points

Unable to boot into Windows after partitioning MacOS

Hello all,

I could see quite a few of the posts having similar issues as I do, but I struggle to follow the steps as I do not understand the terminal commands that follows.

Background,

I have tried to partition a portion of my MacOS disk space in attempt to later combine it into the windows (Bootcamp) partition to extend its space.

However, having done the partition part, I was then unable to boot into windows.

I have then went back into diskutilities and removed that partition (with the "-" sign) which i suppose it is then recombined to my MacOS disk. However, the problem still persists.


I am running on a Late2012 IMac currently running Mojave.


Appreciate the help with this!

Thank you.

iMac 27″, macOS 10.14

Posted on Jun 4, 2020 6:05 AM

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User profile for user: Loner T
Loner T
User level: Level 9
59,536 points

Posted on Jun 4, 2020 7:25 AM

Install GPT Fdisk (aka gdisk).


Rebuild MBR to match the new GPT information thus resetting the Hybrid MBR. Use defaults for other questions (like partition codes). The only values that need modifications are the Boot flags and step 10. Accept all other defaults that Gdisk offers. Please see the sample Q&A as an example. These steps can be repeated if you make a mistake before you get to Step 12, otherwise start from Step 1 for these steps. Step 6 has numbers which are typed with a space between the numbers. Please see the sample Q&A before you execute these steps.


  1. Sudo gdisk /dev/rdisk0
  2. P (Print list of parts)
  3. R (Recover)
  4. O (print current Hybrid MBR)
  5. H (chooses Hybrid)
  6. Partitions numbers to be hybridized: 2 3
  7. Y (Good for GRUB question)
  8. N (part 2 boot flag)
  9. Y (part 3 boot flag make NTFS bootable partition)
  10. O (print current Hybrid MBR)
  11. W (Write the new MBR)
  12. Y (Yes! write the new MBR)
  13. Reboot


Here is sample Q&A for this section. Please notice the Press Enter/Return.


Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): Y

Creating entry for GPT partition #2 (MBR partition #2)
Enter an MBR hex code (default AF): Press Enter/Return
Set the bootable flag? (Y/N): N

Creating entry for GPT partition #3 (MBR partition #3)
Enter an MBR hex code (default 07): Press Enter/Return
Set the bootable flag? (Y/N): Y


Test 1 - Does Bootcamp Volume show up in Finder?

Test 2 - Can you see files in Bootcamp Volume?

Test 3 - Can you select Bootcamp in System Preferences -> Startup Disk?

Test 4 - If Test 3 is successful, select Bootcamp and Click Restart.

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Question marked as Top-ranking reply
User profile for user: Loner T
Loner T
User level: Level 9
59,536 points

Jun 4, 2020 7:25 AM in response to Hikarikaze

Install GPT Fdisk (aka gdisk).


Rebuild MBR to match the new GPT information thus resetting the Hybrid MBR. Use defaults for other questions (like partition codes). The only values that need modifications are the Boot flags and step 10. Accept all other defaults that Gdisk offers. Please see the sample Q&A as an example. These steps can be repeated if you make a mistake before you get to Step 12, otherwise start from Step 1 for these steps. Step 6 has numbers which are typed with a space between the numbers. Please see the sample Q&A before you execute these steps.


  1. Sudo gdisk /dev/rdisk0
  2. P (Print list of parts)
  3. R (Recover)
  4. O (print current Hybrid MBR)
  5. H (chooses Hybrid)
  6. Partitions numbers to be hybridized: 2 3
  7. Y (Good for GRUB question)
  8. N (part 2 boot flag)
  9. Y (part 3 boot flag make NTFS bootable partition)
  10. O (print current Hybrid MBR)
  11. W (Write the new MBR)
  12. Y (Yes! write the new MBR)
  13. Reboot


Here is sample Q&A for this section. Please notice the Press Enter/Return.


Place EFI GPT (0xEE) partition first in MBR (good for GRUB)? (Y/N): Y

Creating entry for GPT partition #2 (MBR partition #2)
Enter an MBR hex code (default AF): Press Enter/Return
Set the bootable flag? (Y/N): N

Creating entry for GPT partition #3 (MBR partition #3)
Enter an MBR hex code (default 07): Press Enter/Return
Set the bootable flag? (Y/N): Y


Test 1 - Does Bootcamp Volume show up in Finder?

Test 2 - Can you see files in Bootcamp Volume?

Test 3 - Can you select Bootcamp in System Preferences -> Startup Disk?

Test 4 - If Test 3 is successful, select Bootcamp and Click Restart.

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User profile for user: Hikarikaze
Hikarikaze Author
User level: Level 1
4 points

Jun 4, 2020 6:26 AM in response to Hikarikaze

Adrians-iMac:~ adriantok$ diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *500.3 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_APFS Container disk1 300.1 GB disk0s2

3: Microsoft Basic Data BOOTCAMP 200.0 GB disk0s3


/dev/disk1 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +300.1 GB disk1

Physical Store disk0s2

1: APFS Volume Macintosh HD 147.9 GB disk1s1

2: APFS Volume Preboot 32.1 MB disk1s2

3: APFS Volume Recovery 510.1 MB disk1s3

4: APFS Volume VM 2.1 GB disk1s4


Adrians-iMac:~ adriantok$ sudo gpt -vv -r show /dev/disk0

Password:

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

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

gpt show: /dev/disk0: Pri GPT at sector 1

gpt show: /dev/disk0: Sec GPT at sector 977105059

start size index contents

0 1 PMBR

1 1 Pri GPT header

2 32 Pri GPT table

34 6

40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

409640 586072024 2 GPT part - 7C3457EF-0000-11AA-AA11-00306543ECAC

586481664 390623232 3 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

977104896 131

977105027 32 Sec GPT table

977105059 1 Sec GPT header

Adrians-iMac:~ adriantok$ sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 60821/255/63 [977105060 sectors]

Signature: 0xAA55

Starting Ending

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

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

1: EE 1023 254 63 - 1023 254 63 [ 1 - 977105059] <Unknown ID>

2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

3: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

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

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Unable to boot into Windows after partitioning MacOS

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