Boot Camp is no longer visible in OS X but is bootable via ALT

Question

Boot Camp is no longer visible in OS X but is bootable via ALT

Greetings,

I'm running a MacBook Pro (mid 2010) Yosemite 10.10.2, 1TB HDD, 8GB RAM, Windows 7 Ultimate in Boot Camp.

I have a very similar situation to that of gytis90210who wrote this thread:

Bootcamp partition is no longer visible and bootable

Like gytis90210 I had a situation where I needed to increase my Boot Camp partition and I followed the same instructions that he or she did:

how to resize my bootcamp partition without deleting itit

Essentially what I did was to, from the OS X side, use Disk Utility to reduce the size of my primary MAC OS partition, and then switch to the Windows side, my BOOT CAMP partition, and using a free app called Mini Tool Partition Wizard (MTPW) expand my Boot Camp partition. Everything on the Windows side worked without a hitch, just as in this YouTube tutorial. However, when I returned to the OS X side I noticed that BOOT CAMP was no longer visible as a volume in the side bar of Finder. I double checked this anomaly using Disk Utility and noticed that my OS X partition did in fact reduce to ~ 900 GB from its previous ~980 GB, but my Boot Camp partition was somehow renamed disk0s4, and the size seemed to remain at ~20 GB instead of the increased ~100 GB I achieved on the Windows side using MTPW.

Unlike gytis90210 I am able to switch between MAC OS and BOOT CAMP (DISK0S4 ?) using the ALT key during restart without any problem. For this I am grateful. However, this situation poses a significant problem when it comes to backing up my volumes. I use Data Backup 3 (DB3) to regularly do versioned backups of my entire HDD and now it can't find Boot Camp to backup that volume.

In the above cited thread by gytis90210, "Bootcamp partition is no longer visible and bootable", a Level 5 community member named Loner T assisted in solving the problem. Both gytis90210 and Loner T appear to be familiar with and competent in using Terminal. Regrettably I am unfamiliar with using this advanced tool, but am willing to try if someone is patient and willing to walk me through the steps. It appears, based on Loner T's ability to assist gytis90210 that this problem is solvable, however, I do not want to assume that the steps used in gytis90210's case will be the same in mine. So I haven't attempted to duplicate this solution in my situation. I fear by tinkering "under the hood" with Terminal might cause more problems since I really wouldn't know what I was doing. Hence, I am appealing to those who, like Loner T, are savvy in using Terminal and who can aid me in solving this issue.

Alternatively, and perhaps as a last resort, I am curious if using Disk Utility I can just delete DISK0S4 and create a new BOOT CAMP partition of the desired size and then just restore its contents via DB3's restore function? I've contacted Prosoft Engineering, the makers of DB3, and inquired if DB3 backsup the OS in Boot Camp as well as all my other data. Here is their reply:

"Data Backup was not made or intended to be used with NTFS formatted volumes such as your bootcamp volume. We cannot provide suggestions for the operation you are trying to perform as we do not support it not [sic] have we tested it even though Data Backup may backup those files."

When I look at my backed up volume it appears to include a Windows folder that has all the components of Windows 7, but I cannot be certain that this will indeed restore Boot Camp to its pre-problem state. Perhaps someone more familiar with restoring Boot Camp in this manner might shed light on the situation. Here's a screenshot of what my DB3 compressed backed up BOOT CAMP volume looks like if it'll help:

Any assistance will be greatly appreciated. Thank you kindly in advance.

MacBook Pro, OS X Yosemite (10.10.2)

Posted on Mar 19, 2015 11:23 AM

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Answer 1

Best reply

Loner T

Level 9

59,471 points

Mar 19, 2015 11:53 AM in response to Señor Magnifico

Apple does not support resizing/re-partitioning of single-disk OSX and Bootcamp Macs. There is a mapping called a Hybrid MBR which is setup between the Apple partitioning method called GUID Partition Table (GPT) and legacy BIOS emulated Windows installations. If DU and other tools are used to resize partitions, the MBR (used by Windows) and GPT (used by OSX) are out of sync. OSX uses the GPT information to allow the ability to read the NTFS volume used by Windows. If it does not match, you will see the behavior observed, which is that OSX cannot read the Windows volume.

From OSX Terminal, please post the output of the following commands. The "sudo" requires your password, which is not echoed back to you. It may also warn you about improper use of sudo and potential data loss, if abused.

sudo gpt -vv -r show /dev/disk0

sudo fdisk /dev/disk0

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Answer 2

Mar 19, 2015 1:12 PM in response to Loner T

Greetings Loner T,

Thank you for your kind response. I must confess that I had to do a Google as well as Wikipedia search to look up the terms you used; MBR, GUID, & GPT. And even after doing so I only barely have an idea of what these mean. Nevertheless, I trust your expertise in this regard.

Here are the outputs you requested from Terminal using the indicated commands:

Output from: sudo gpt -vv -r show /dev/disk0

gpt show: /dev/disk0: mediasize=1000204886016; sectorsize=512; blocks=1953525168

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 1953525167

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 1757738528 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

1758148168 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

1759417704 664

1759418368 155045888 4

1914464256 39059456 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

1953523712 1423

1953525135 32 Sec GPT table

1953525167 1 Sec GPT header

Admins-MacBook-Pro:~ User$

Output from: sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 121601/255/63 [1953525168 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: AF 25 127 15 - 1023 254 63 [ 409640 - 1757738528] HFS+

3: AB 1023 254 63 - 1023 254 63 [1758148168 - 1269536] Darwin Boot

*4: 07 1023 254 63 - 1023 254 63 [1759418368 - 194105344] HPFS/QNX/AUX

Admins-MacBook-Pro:~ User$

Thanks for your assistance!

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Answer 3

Loner T

Level 9

59,471 points

Mar 19, 2015 1:38 PM in response to Señor Magnifico

This may be a relatively easy problem to fix. Since your MBR (the Fdisk output) is correct and it allows you to boot Windows, if you notice, in the output from "gpt" command, you have

1759418368 155045888 4

1914464256 39059456 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

and the fdisk output shows

*4: 07 1023 254 63 - 1023 254 63 [1759418368 - 194105344] HPFS/QNX/AUX

This difference in the GPT is responsible for the issue. If you also notice, the first three entries match in start/size columns, but the last entry does.

If you can download GPT Fdisk (http://sourceforge.net/projects/gptfdisk/), and install it, it can be fixed. I can provide you the steps to fix this and test.

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Answer 4

Mar 19, 2015 1:51 PM in response to Loner T

Greetings Loner T,

I downloaded GPT Fdisk (GDisk) and installed it. I presume it installed correctly. Where it went, I'm not sure. It's not located in my Apps but I suspect that it loaded to the proper place it's supposed to be.

I await your instructions.

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Answer 5

Loner T

Level 9

59,471 points

Mar 19, 2015 2:16 PM in response to Señor Magnifico

If you type the following highlighted command in a Terminal window, you should get a response matching what I have posted.

type gdisk

gdisk is /usr/sbin/gdisk

The following steps delete the current GPT 4 entry and combine the missing part to create a proper BC volume. The explanation of the what each command does is included in parentheses. The values in steps 7 and 8 came from the last entry in your Fdisk output.

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)
1759418368 - Start offset in bytes (start point for Bootcamp part)
+194105344(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.

Reboot.

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

Mar 19, 2015 3:35 PM in response to Loner T

Greetings Loner T,

After carefully following the steps you delineated above the problems appears to be solved! Woohoo!

As far as Tests 1- 3, here is the evidence of the success both in Finder and System Preferences > Startup Disk:

And here is evidence from Disk Utility as well:

And here is evidence that Test 4 being a success this is what I saw:

But the BEST part is that DB3 now recognizes that I have a BOOT CAMP partition and I am able to backup my entire system again!

Thank you so very much for your expert and timely assistance. And thanks for the time it took you to garner the knowledge to arrive at your present point to be able to help far less knowledgeable folks such as myself. Not only this, but your willingness to assist others in this capacity is deeply appreciated for the simple reason that because you excel in getting the computers of others to function properly again it allows them to return to excelling at what they do best. I know that this is so in my case. Much thanks!

Respectfully,

Señor Magnifico

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