Another Win7 Bootcamp failure with Yosemite upgrade (missing 34 GB)

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Another Win7 Bootcamp failure with Yosemite upgrade (missing 34 GB)

I've been reading what others have been doing per Loner T's instructions, but I'm a bit unclear on the ultimate goal, particularly when using testdisk and looking for "familiar files." I'm hoping for some instructions on how to recover my Win7 partition. I'm running a testdisk deeper search, but again I'm not sure what I'm looking for in that program or if I've followed the correct selections. Here are the outputs from the 4 commands that Loner T has said to provide...

Huge thanks in advance for any help.

MacBook Pro with Retina display, OS X Yosemite (10.10)

Posted on Oct 28, 2014 6:48 AM

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Answer 1

andrewjf33 Author

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Oct 28, 2014 6:58 AM in response to andrewjf33

I should also mention, I tried these steps:

Try the simple first step first to see if it works.

sudo fdisk -e /dev/disk0

setpid 4

07

flag 4

p

w

y

Reboot.

And now when I restart and hold option, I see the Windows partition, but it says Disk Read Error or something like that. It still doesn't show in Finder, About This Mac, System Info., etc.

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Answer 2

andrewjf33 Author

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Oct 28, 2014 7:02 AM in response to andrewjf33

Here's the output of...

sudo dd if=/dev/rdisk0s4 count=1 2>/dev/null | hexdump -C

I see that R.NTFS at the top, which from what I've read is what we're looking for?

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Answer 3

Loner T

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Oct 28, 2014 7:05 AM in response to andrewjf33

Yosemite is corrupting your Bootcamp volume. Notice the gap between GPT#3 and GPT#4.

Using Testdisk, there are two goals, use Quick Search to find NTFS headers, which is usually onto very successful, but Deeper Search shows "missing" NTFS headers. One of these headers has your pre-Yosemite NTFS partition, which needs to be resuscitated. In most cases, it is sitting between GPT#3 and #4, the "missing" 34GB, in your case.

Please use this thread - Yosemite Upgrade Broke Bootcamp as an example of Testdisk and Gdisk usage.

If you are unclear, please post back on this thread, and I will do my best to assist.

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Answer 4

andrewjf33 Author

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Oct 28, 2014 7:27 AM in response to Loner T

So here's the results of a Quick Search:

Inside the MS Data selection:

The top MS Data and the bottom one both show "Can't open filesystem" when I use P: list files, but the middle one (size = 191678457) has that System Volume Information file you mentioned in the thread, along with some other recognizable file names, though there are a few key programs I had installed that I don't see, but I'm hoping they'll still be there when we recover the partition. Here's that file highlighted, and I put red boxes around what I think are the "start" and "end," are those correct?

In the other thread, you go on to say "If this is the only MS data entry..." but I have 3 I think, so will I need to do something different than fhornedo?

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Answer 5

Loner T

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Oct 28, 2014 8:04 AM in response to andrewjf33

The highlighted number in the last screen shot are start/size, not start/end. The triplet is start/end/size.

Your GPT#3 (Recovery HD) ends at 298554175. The next byte is 298554176 where the "gap" starts. Testdisk shows a valid NTFS header at 298555392 (+1216 bytes) after 298554176. The current NTFS header you see is the corrupted (by Yosemite) header. It is bogus.

Please delete the current GPT#4, and create a new one starting at 298555392 with size of 191678457 which ends at 490233848. The next entry is at 490233856 (+8 bytes, which is due to sector alignment).

The steps are in the other thread, as long as you use your specific start/end/size. Let me know if you need any assistance on the exact steps after you look at the referenced article.

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Answer 6

andrewjf33 Author

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Oct 28, 2014 10:07 AM in response to Loner T

I think I'm in good shape, Tests 1-3 are good, I can see the Bootcamp volume in Finder, Startup Disk, and there are files inside. I thought I'd share the outputs from the three commands that you mentioned in the other thread before continuing to Step 5 (new Hybrid MBR).

The hex dump -C command has NTFS in the first line, so it's good. In the second photo (sudo gpt -vv...), I notice there's still a gap between GPT 3 & 4, but it's just very small. Is this expected?

Time to create the Hybrid MBR?

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Answer 7

Loner T

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Oct 28, 2014 10:15 AM in response to andrewjf33

Yes, please.

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Answer 8

andrewjf33 Author

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Oct 28, 2014 10:35 AM in response to Loner T

Currently replying from Windows 7 on my Mac! Thanks so much for your help, worked like a charm.

So now, I have a Time Machine backup on an external HD of my Mac OS partition from before I upgraded to Yosemite. I'm tempted to revert back to Mavericks because it seems like a much more solid, stable OS. Would you recommend doing that? And if so, would that involve booting in Target Disk Mode or something like that? Or just plugging in the HD and reverting?

Thanks again, can't describe how much I appreciate your help.

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Answer 9

Loner T

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Oct 28, 2014 10:48 AM in response to andrewjf33

Glad it worked out. 😎

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Answer 10

olypdd

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Oct 28, 2014 12:41 PM in response to Loner T

Loner T, I commend your assisting folks as you have. I see your hard work all over the forums.

I have a nagging question about this problem. Is this only occurring in machines with SSD or hybrid drives....AND, only in machines where folks have either resized or added partitions other than the base OSX and Bootcamp/Windows partions?

I ask because in some forums, it "sounds" like folks who upgrade FROM OSX haven't had a problem....but then it's not clear if this is consistently the case or just some lucky people.

I have a late 2013 MBP Retina with SSD with OSX, Bootcamp, and I assume one for restoring my OS if needed. I'd love to upgrade but don't want to nuke and pave. Such a process reinstalling Windows and it works great and don't want to mess with it.

I had no issues with my older 17" MBP (mid 2010). I upgraded to Yosemite from OSX and no problems with bootcamp whatsoever. But it is a hard DISK and NOT ssd.

Thanks again.

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Answer 11

Loner T

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Oct 28, 2014 12:51 PM in response to olypdd

I have no evidence that supports that SSDs are prone to this problem more than HDDs or vice-a-versa.

Here is a collection of threads https://discussions.apple.com/thread/6605135 which have had similar issues. Some folks had 750Gb HDDs, while some others had 256Gb SSDs. It is a mixed bag. Most of the machines are SATA machines. There are two iMac 5K Retinas with Fusion drives.

I will try and collect more information to see if there is any additional evidence that provides such correlation, positive or negative.

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Answer 12

olypdd

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Oct 28, 2014 12:54 PM in response to Loner T

Interesting. Well, until it's clear I'm an exception to this mess or Apple sends out an updated upgrade to address it, I'll wait since my retina machine is now my primary workhorse.

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Answer 13

Loner T

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Oct 28, 2014 1:04 PM in response to olypdd

If you can wait till Yosemite stabilizes, it is worth waiting for.

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