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fallen002 Author

Level 1

0 points

Can't boot from bootcamp after sudden crash

Hi,

So today I was playing cs:go, running bootcamp, when suddenly my mac crashed and rebooted to mavericks... I've tried several things on this thread but I still can't boot on bootcamp... I really need some files I have there and I can't access them -.-' Is there a way to fix this and get bootcamp to work again? Tell me what you need from terminal so I can upload it here.

Btw, when I created the bootcamp partition I created it with 100gb and later I upgraded it to 400gb without reinstalling bootcamp but it as worked fine for more than a month so I'm assuming that is not the problem...

I really need some help with this...

Thanks,

Gabriel

iMac, OS X Mavericks (10.9.2)

Posted on Sep 23, 2014 5:45 PM

Top-ranking reply

Loner T

Level 9

59,513 points

Posted on Sep 23, 2014 6:22 PM

1. The ~300 GB is sitting right above the GPT#4 entry. Your NTFS header is corrupt.

2. You have two NTFS entries. GPT#4's start/size match the entry #3 in the Fdisk output, but is unbootable (the missing "*").

3. The Fdisk entry #4 has all zeroes and is bootable, but has invalid start/size (0/0).

4. Download GPT Fdisk from SourceForge.net. (http://sourceforge.net/projects/gptfdisk/).

5. Run sudo gdisk /dev/disk0. Delete GPT#4 entry.

6. Add GPT#4 again with start = 1206448520, end=1953525134 (1 before the SEC GPT Table start). You will lose Recovery HD. If you need it, use Command+R to re-install OS X after Windows is functional (not before).

7. In Gdisk, re-create a Hybrid MBR with 2 3 4 (and allow it to add the EFI into the MBR). If you need step-by-step, please post back here.

8. Reboot into OS X.

9. Verify that Bootcamp volume is visible in Finder.

10. Verify that you can see files in Bootcamp volume in Finder.

11. Verify that you can select Bootcamp in System Preferences -> Startup Disk.

12. Select Bootcamp and reboot.

If there are any error messages, please stop and post back here.

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32 replies

fallen002 Author

Level 1

0 points

Sep 24, 2014 5:14 PM in response to Loner T

well, I'm trying to solve the problem but this is so confusing... I don't really know how to recover the partition when this shows so many things..

EDIT: I think I had 400gb on my windows partition

fallen002 Author

Level 1

0 points

Sep 24, 2014 5:20 PM in response to fallen002

Inicially I had 100gb but than I upgraded it to 400gb. BTW Testdisk says it has no write access, what can I do about this?

Loner T

Level 9

59,513 points

Sep 24, 2014 5:31 PM in response to fallen002

Testdisk is being run on a disk which is mounted and running OS X, so it will complain about read-write access. Select Continue and press return.

Pick EFI and look for entries that say MS Data and check each one. Do not use right or left arrow, just up and down when moving in the partition list.

You want to use the "P: List files" option.

fallen002 Author

Level 1

0 points

Sep 24, 2014 5:41 PM in response to Loner T

so I found my files but how do I recover the partition? I have a lot of D's saying that it will be deleted but I got my files in there, what exactly should I do?

Loner T

Level 9

59,513 points

Sep 24, 2014 5:55 PM in response to fallen002

You should have only one MS Data which has your files that look familiar. If you can post a screen shot with the start/end/size then the GPT needs to be recreated using these values in Step 6.

fallen002 Author

Level 1

0 points

Sep 24, 2014 7:22 PM in response to Loner T

I got two but I don't even know what to do with this program or whatever this is....

Loner T

Level 9

59,513 points

Sep 24, 2014 7:50 PM in response to fallen002

Click on Quick Search and press return.

You should get multiple MS Data entries. Pick the first and use P: List files.

If the files look familiar, press Return to continue.

You should see a Deeper Search Option. Press enter on that.

Check your files. If they look familiar, note down the start/end/size, or paste a screen shot here for a record.

Repeat the same for the second one. Note down the start/end/size of any partition that looks familiar.

Once you have a list of all start/end/size which contain familiar files, the GPT needs to be modified to match that specific start/end, and run the dd command to check for NTFS header. If you get an NTFS header, that is the correct start of your disk. With this as GPT#4 from Step 6, execute Step 7. Verify the files in Finder, Startup Disk, etc.

If it works, then switch to Windows. You may need Windows Startup repair to be able to boot because your boot sector may be corrupted.

fallen002 Author

Level 1

0 points

Sep 25, 2014 12:19 PM in response to Loner T

Here's the result of the Deep Search...

I can't check any files in here, only press continue... So once again I don't know what to do with this...

Loner T

Level 9

59,513 points

Sep 25, 2014 2:06 PM in response to fallen002

Please use down/up arrow to select the first MS Data partition, and then check "P: List Files", if the files look familiar, please note down start/end/size, and repeat this for each MS Data entry.

fallen002 Author

Level 1

0 points

Sep 28, 2014 8:51 AM in response to Loner T

So, after a while, I got this..

Start End

1206450176 1953523704

1815727832 1815734005

1815734024 1815740197

1815740216 1815746389

1816648200 1816654373

Once you have a list of all start/end/size which contain familiar files, the GPT needs to be modified to match that specific start/end, and run the dd command to check for NTFS header. If you get an NTFS header, that is the correct start of your disk. With this as GPT#4 from Step 6, execute Step 7. Verify the files in Finder, Startup Disk, etc.

What should I do now? I can see what to do but I don't know how to do it

Loner T

Level 9

59,513 points

Sep 28, 2014 9:59 AM in response to fallen002

For each of the start/end pairs, execute the following...

1. Delete the old entry and create a new entry at GPT#4.

sudo gdisk /dev/disk0

(Put the correct Start value here)

(Put the correct End value here)

2. You will need to reboot after each change, because the disk you are booted from is the one being modified. Each reboot will rebuild disk0s4 using the start/end you entered.

3. Run the dd command - sudo dd if=/dev/rdisk0s4 count=1 2>/dev/null | hexdump -C and check that the first line contains "R.NTFS".

4. If you want to pose here for recording purposes, each of these iterations, please do so. It may be better that the output of 1,2,3 gets recorded here.

5. This is a tedious process and you want to check after the second 'p'rint command that it looks reasonable, before the 'w'rite and 'y'es to confirm.

fallen002 Author

Level 1

0 points

Sep 28, 2014 12:07 PM in response to Loner T

so I need to delete and create the partition again and again until I find the one I can boot from, is that it? Meaning, reboot until it says "R.NTFS", correct? When I see that I stop doing it and I'll be able to boot from windows or do I have to do something else?

Loner T

Level 9

59,513 points

Sep 28, 2014 1:01 PM in response to fallen002

Once the correct NTFS partition has been located,

1. A new Hybrid MBR reflecting the GPT needs to be recreated using Gdisk.

2. It should be tested for

a. Bootcamp volume shows up in Finder.

b. Windows files are visible.

c. System Preferences -> Startup allows Bootcamp to be selected.

d. At this point a switch is possible, but may need Windows Startup repair to make the boot loader/manager and boot sector be available for a clean switch

between the two OSes.

fallen002 Author

Level 1

0 points

Sep 28, 2014 5:01 PM in response to Loner T

well, I can now see the bootcamp on finder and access my files... just did the hybrid MBR thing and will now try to reboot on windows. Thanks for the help, I'll let you know if it worked 😉

Loner T

Level 9

59,513 points

Sep 28, 2014 6:17 PM in response to fallen002

Does the disk show up in System Preferences -> Startup Disk? If yes, the only remaining issue might be a Startup Repair.

Can't boot from bootcamp after sudden crash