"Missing Operating System" After Partition Resizing and MBR Repair

Question

"Missing Operating System" After Partition Resizing and MBR Repair

Hi.

I have a Macbook Pro Retina with Bootcamp/Windows 7. I resized the partition and lost the ability to log into Windows when holding down "alt/option" on startup. I did the MBR repair that LonerT posted and now I can select Windows on startup but it's just a black screen that says "Missing Operating System". I tried using Windows startup recovery with no success. Looking for help to access Windows again because I have a ton of work saved on there.

diskutil list

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *251.0 GB disk0

1: EFI 209.7 MB disk0s1

2: Apple_HFS Macintosh HD 50.0 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

4: Microsoft Basic Data 125.1 GB disk0s4

/dev/disk1

#: TYPE NAME SIZE IDENTIFIER

0: FDisk_partition_scheme *16.0 GB disk1

1: DOS_FAT_32 WININSTALL 16.0 GB disk1s1

sudo gpt -vv -r show /dev/disk0

Password:

gpt show: /dev/disk0: mediasize=251000193024; sectorsize=512; blocks=490234752

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

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

gpt show: /dev/disk0: Sec GPT at sector 490234751

start size index contents

0 1 MBR

1 1 Pri GPT header

2 32 Pri GPT table

34 6

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

409640 97656248 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

98065888 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

99335424 146486016

245821440 244412416 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

490233856 863

490234719 32 Sec GPT table

490234751 1 Sec GPT header

sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 30515/255/63 [490234752 sectors]

Signature: 0xAA55

Starting Ending

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

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

1: EE 0 0 2 - 1023 254 63 [ 1 - 245821439] <Unknown ID>

*2: 07 1023 254 63 - 1023 254 63 [ 245821440 - 244412416] HPFS/QNX/AUX

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

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

Posted on Jul 27, 2015 1:31 AM

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Answer 1

Loner T

Level 9

59,471 points

Jul 27, 2015 3:51 AM in response to bostonhatcher

You have a large gap between GPT3 and GPT4 which indicates a lost NTFS header. It may be possible to recover Windows.

Can you look at Windows 7 Vanished after Yosemite update... help? as a reference and download Testdisk and GPT Fdisk and start a Testdisk scan?

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Answer 2

Jul 27, 2015 8:54 AM in response to Loner T

Is this the quick search results?

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Answer 3

Loner T

Level 9

59,471 points

Jul 27, 2015 9:13 AM in response to bostonhatcher

Scroll down to the first MS Data and use 'P' to list files. Hit Escape only once after you get the output, and then back on this screen scroll down to the second one and use the 'P' command on the second one. The most likely candidate is the first MS Data.

We are looking for something similar to

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Answer 4

Jul 27, 2015 9:19 AM in response to Loner T

Yes the first MS Data gave me

The second MS Data gave me

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Answer 5

Loner T

Level 9

59,471 points

Jul 27, 2015 9:44 AM in response to bostonhatcher

Using the first screen, here is a verification table.

GPT 3 Start	GPT 3 Size	GPT 3 End	NTFS Start	Sector Offset	NTFS Size	NTFS End	Sector Offset (MB)	NTFS(Gb)
98065888	1269536	99335424	99336192	768	390897657	490233848	0	186.3945279

Install GPT Fdisk (aka gdisk). Leave your Testdisk display and start a new Terminal Window. You need to use the following steps. If you see any error messages during the following steps, please stop and post back here with the error message. The following steps have values from your Testdisk output (and you can verify) in Steps 7 and 8. Please notice the'+' sign in step 8 (this is called offset notation). The text in parentheses is for informational purposes to describe the action being taken. Gdisk has one-character commands except when entering numbers.

Rebuild GPT4 using start/end offsets

Sudo gdisk /dev/rdisk0
P (print the full list of parts)
D (delete)
4 (part 4)
N (new part)
4 (part 4)
9936192 ( - Start offset in sectors or the start point for Bootcamp part)
+390897657 ( - Size offset, as opposed to End offset)
0700 (Windows part type)
P (print list of all parts just to see what changes will be made)
W (Write the new GPT)
Y (Yes! really write the new GPT)

This will delete and re-write the GPT partition info for /dev/disk0s4.

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 thesample 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.

Sudo gdisk /dev/rdisk0
P (Print list of parts)
R (Recover)
O (print current Hybrid MBR)
H (chooses Hybrid)
Partitions numbers to be hybridized: 2 3 4
Y (Good for GRUB question)
N (part 2 boot flag)
N (part 3 boot flag)
Y (part 4 boot flag make NTFS bootable partition)
O (print current Hybrid MBR)
W (Write the new MBR)
Y (Yes! write the new MBR)
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 AB): Press Enter/Return

Set the bootable flag? (Y/N): N

Creating entry for GPT partition #4 (MBR partition #4)

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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Answer 6

Jul 27, 2015 11:06 AM in response to Loner T

Test 3 was successful. Windows would not start successfully so I ran the startup repair. I then restarted and it just freezes on the starting windows page.

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Answer 7

Loner T

Level 9

59,471 points

Jul 27, 2015 11:19 AM in response to bostonhatcher

Can you post the output of

sudo gpt -vv -r show /dev/disk0

sudo fdisk /dev/disk0

Do you have any third-party NTFS software?

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Answer 8

Jul 27, 2015 11:25 AM in response to Loner T

I don't think I have any third-party ntfs software. How would I know?

sudo gpt -vv -r show /dev/disk0

Password:

gpt show: /dev/disk0: mediasize=251000193024; sectorsize=512; blocks=490234752

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

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

gpt show: /dev/disk0: Sec GPT at sector 490234751

start size index contents

0 1 MBR

1 1 Pri GPT header

2 32 Pri GPT table

34 6

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

409640 97656248 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

98065888 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

99335424 768

99336192 390897657 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

490233849 870

490234719 32 Sec GPT table

490234751 1 Sec GPT header

sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 30515/255/63 [490234752 sectors]

Signature: 0xAA55

Starting Ending

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

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

1: EE 0 0 2 - 25 127 14 [ 1 - 409639] <Unknown ID>

2: 03 25 127 15 - 1023 254 63 [ 409640 - 97656248] XENIX /usr

3: 03 1023 254 63 - 1023 254 63 [ 98065888 - 1269536] XENIX /usr

*4: 03 1023 254 63 - 1023 254 63 [ 99336192 - 390897657] XENIX /usr

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Answer 9

Loner T

Level 9

59,471 points

Jul 27, 2015 12:14 PM in response to bostonhatcher

The MBR is incorrect. Please re-execute the second set of Gdisk steps and see the following.

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 AB): Press Enter/Return

Set the bootable flag? (Y/N): N

Creating entry for GPT partition #4 (MBR partition #4)

Enter an MBR hex code (default 07): Press Enter/Return

Set the bootable flag? (Y/N): Y

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Answer 10

Jul 27, 2015 12:23 PM in response to Loner T

I'm back in Windows now! Thank you so much Loner T for your time and effort. You're the man!

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Answer 11

Loner T

Level 9

59,471 points

Jul 27, 2015 1:19 PM in response to bostonhatcher

Please back up OSX and Windows to separate appropriately-formatted external disks as a baseline for future recovery.

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