I have corrupted my mac partitions with bootcamp

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Level 1

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I have corrupted my mac partitions with bootcamp

I recently installed bootcamp to dual boot my MBP into OSX and Windows. I have several work specific applications that are windows based, and thought this would be a great time saver.

The initial install went fine, and I got a dual boot up and running. I could switch back and forth at will with no problems. Then the latest windows update came out, and needed more hard drive space. (I'm sure you see where this is going.) I used partition magic in Windows to shrink my mac partition slightly and increase my windows partition enough for the update.

Windows boots fine, but now this is my only visible operating system.

When i boot into internet recovery mode, and run disk utility, it sees the partition, but it is completely grayed out, and I cannot run a verify or repair on it. I'm fairly certain the windows partition tool has corrupted or deleted my MBR and/or GPT.

The data and files are still there, its just in an unmountable volume that I can't get to.

Is there a way to repair these partition tables without wiping and reinstalling OSX? I back up regularly at the file level, but missed a few financial files recently that would be nearly impossible to recreate. Any advice would be super helpful.

**Another note, the same partition tool i used in windows to resize things does have a partition recovery tool. When scanning, it did identify two partitions that are no longer there. I haven't used this tool yet, as I'm afraid it may make things worse. But, it could be there as a last resort if nothing else can solve this.

MacBook Pro 13", macOS 10.14

Posted on Jun 19, 2019 2:52 PM

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Answer 1

Best reply

BDAqua

Level 10

239,861 points

Jun 19, 2019 3:07 PM in response to aejeffor

Oh, you can't use anything to partition the disk for Bootcamp other than Bootcamp.

Can you get another external drive to install OSX to & try to recover those important files from the borked drive?

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Answer 2

BDAqua

Level 10

239,861 points

Jun 19, 2019 7:37 PM in response to aejeffor

There are no tools for APFS yet, the only cure has been to boot from another drive running High Sierra, then if the files can be read use something like CCC to clone the APFS drive to another drive that is HFS+, then erase the APFS drive back to HFS+, then clone back to the freshly formatted HFS drive, then bioot from it & let it get APFSed automatically...

Carbon Copy Cloner...

http://www.bombich.com/software/ccc.html

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Answer 3

aejeffor Author

Level 1

8 points

Jun 26, 2019 5:40 AM in response to BDAqua

Thanks for all the advice. I got back to normal, but not without a lot of headache, and some lost files. I ended up doing the following.

Creating an OSX bootable USB drive
Booted into that
Purchased Easus Data Recovery for Mac (after testing several others)
Scanned the affected drive, and recovered about 95% of it to an external HD
I then wiped the internal HD and did a fresh reinstall of OSX
Redownloaded and installed all my applications
Pulled data files, as needed, from the external HD where I restored the old data to in step 4.

I only ran across one file I couldn't restore. Unfortunately, it was my quicken data file that had at least 10 years worth of personal finance records in it. :/ By chance, about 3 weeks ago, I upgraded my icloud storage plan and also checked the box to sync my documents there. (I had completely forgotten I did this) So, many of my important files were also restored automatically when I signed into icloud on the "new" OS.

I used virtual box to setup several virtual machines now instead of fussing with partitions, bootcamp, etc. Much cleaner and easier.

Lessons Learned:

If you use bootcamp, don't mess with partitions on the windows side - ever.
Backup, backup, backup... and backup your backups.
Data recovery tools actually do work, and are worth the $50-$100 sometimes
Manually repairing the GPT table with start points and offset amounts actually helps the system see and/or mount the affected drive, but it won't "uncorrupt" a file that has been damaged in a bootcamp experiment.
Virtual machines within OSX is much simpler to accomplish the same result.

Lessons Learned:

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Answer 4

aejeffor Author

Level 1

8 points

Jun 19, 2019 4:01 PM in response to BDAqua

I can but not sure what to do once I boot up the new OS X drive. Do I just attach the old drive and mount it?

i was hoping there is a way to repair the partition tables correctly and avoid the former.

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Answer 5

aejeffor Author

Level 1

8 points

Jun 20, 2019 6:56 AM in response to aejeffor

Downloaded CCC, but it doesn't even see the volume because it's unmounted. DU won't let me mount it either.

I saw some posts on how to correct this using gdisk and Testdisk in combination, but other than those options, I'm afraid I might be SOL?

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Answer 6

HWTech

Level 9

56,168 points

Jun 21, 2019 8:27 PM in response to aejeffor

Instead of Bootcamp you should see if running Windows in a Virtual Machine will work for you depending on the performance needed by your Windows apps. VirtualBox is free, but you can also choose from paid apps such as Parallels and VMWare. It is a lot simpler to configure and backup your whole system and a VM keeps you from hurting macOS. Plus it allows you to easily backup & resize the VMs images. I used to dual boot years ago and it drove me crazy. A VM makes things much nicer and you have access to everything.

IIRC even using Bootcamp Assistant to resize a working Windows partition can lead to Windows not booting. I don't use Bootcamp or Windows now, but I have seen some posts about this issue as well.

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Answer 7

BDAqua

Level 10

239,861 points

Jun 19, 2019 5:49 PM in response to aejeffor

If it's AFPS there's little hope of repairing it, for HFS+ there are many tools better than Disk Utility's First Aid, you can try DU First Aid from the Recovery partition or from another drive.

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