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Boot camp lost after upgrading to Yosemite from mountain lion

I lost my windows7 boot camp after I upgrade to Yosemite from mountain lion. When I press ALT when rebooting there is no more alternative to boot for window anymore. I did read some thread about this but my case is different since when I tried to type 3 steps(diskutil.......etc) 😕 as LonerT user answers it did not work. The attached files here are what I faced with. Please help. I have a lot of important files in windows

MacBook Pro, OS X Yosemite (10.10), macbook pro

Posted on Nov 10, 2014 1:38 PM

82 replies

Loner T

Level 9

59,536 points

Jan 19, 2015 5:43 PM in response to Eugeniu_K

Using the start/end/size from '4' and '5', this is what the numbers look like...

GPT 3 Start	GPT 3 Size	GPT 3 End	NTFS Start	Sector Offset	NTFS Size	NTFS End
720824544	1269536	722094080	722036736	-57344	254734336	976771072
GPT 3 Start	GPT 3 Size	GPT 3 End	NTFS Start	Sector Offset	NTFS Size	NTFS End
720824544	1269536	722094080	722094080	0	254679040	976773120

The negative sector offset means the NTFS header is located somewhere in the current Recovery HD partition. This is the reason for asking if there are any additional files in '4' (because it may be a part of the NTFS partition you are looking for). '5' matches your current GPT 4 partition which is damaged because there is no NTFS header.

If you want, '4' can be used and tested, but you will lose Recovery HD (temporarily), and will have to reinstall OSX after Windows is recovered to rebuild it.

Jan 19, 2015 6:00 PM in response to Loner T

and by reinstalling OSX, won't it break Windows again?

Loner T

Level 9

59,536 points

Jan 19, 2015 6:31 PM in response to Eugeniu_K

Once Windows has been recovered, you should be able to save the GPT, and then install Yosemite again. This should not repeat the problem, because you will already have a CS volume as the destination, but it would be advisable to backup Windows, once it is recovered.

Jan 19, 2015 10:25 PM in response to Loner T

Loner T wrote:

Once Windows has been recovered, you should be able to save the GPT, and then install Yosemite again. This should not repeat the problem, because you will already have a CS volume as the destination, but it would be advisable to backup Windows, once it is recovered.

OK, understood, what should I do next... with '4' , Gdisk?

Loner T

Level 9

59,536 points

Jan 20, 2015 9:43 AM in response to Eugeniu_K

Can you look at Re: Please help, lost windows after Yosemite upgrade execute the steps with Gdisk in rebuilding GPT4 and the Hybrid MBR?

Jan 20, 2015 2:37 PM in response to Loner T

Loner T wrote:

Can you look at Re: Please help, lost windows after Yosemite upgrade execute the steps with Gdisk in rebuilding GPT4 and the Hybrid MBR?

Yes will do the same, but with my numbers:

Using the start/end/size from '4' and '5', this is what the numbers look like...

GPT 3 Start GPT 3 Size GPT 3 End NTFS Start Sector Offset NTFS Size NTFS End

720824544 1269536 722094080 722036736 -57344 254734336 976771072

GPT 3 Start GPT 3 Size GPT 3 End NTFS Start Sector Offset NTFS Size NTFS End

720824544 1269536 722094080 722094080 0 254679040 976773120

So just to be sure

I leave testdisk now and continue with this ?

Rebuild GPT4 using start/end offsets

1.	Sudo gdisk /dev/rdisk0
2.	P (print the full list of parts)
3.	D (delete)
4.	4 (part 4)
5.	N (new part)
6.	4 (part 4)
7.	720824544 - Start offset in bytes (start point for Bootcamp part)
8.	+254734336 (Size offset as opposed to End offset)
9.	0700 (Windows part type)
10.	P (print list of all parts just to see what changes will be made)
11.	W (Write the new GPT)
12.	Y (Yes! really write the new GPT)

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

Loner T

Level 9

59,536 points

Jan 20, 2015 2:53 PM in response to Eugeniu_K

Leave the Testdisk window as is. Start a new Terminal Window (or Tab) and run Gdisk.

Jan 20, 2015 2:59 PM in response to Loner T

Done,

could you please double-check the value from step 7. I think It is not the one, as it is the start of Mac HFS

Loner T

Level 9

59,536 points

Jan 20, 2015 3:42 PM in response to Eugeniu_K

You are correct. They should be as follows. I cut and paste the same value in both places after the calculations. 😟

7. 722036736

8. +254734336

Jan 20, 2015 3:45 PM in response to Loner T

ok thank you, I will proceed now with gdisk. keeping the fingers crossed... 🙂

Loner T

Level 9

59,536 points

Jan 20, 2015 3:46 PM in response to Eugeniu_K

Since only the start/end are being manipulated without any changes to data, they can be corrected, if any issues are encountered. If you see any error messages, please post the error message as well.

Jan 20, 2015 3:47 PM in response to Eugeniu_K

step 2:

Jan 20, 2015 3:50 PM in response to Loner T

something went wrong 😟

Loner T

Level 9

59,536 points

Jan 20, 2015 4:03 PM in response to Eugeniu_K

If I correct the GPT3 start, see the comment below the table. You also need to delete GPT 3, not just GPT 4.

Using the start/end/size from '4' and '5', this is what the numbers look like...

GPT 3 Start GPT 3 Size GPT 3 End NTFS Start Sector Offset NTFS Size NTFS End

722036736 1269536 722094080 722036736 -57344 254734336 976771072

GPT 3 Start GPT 3 Size GPT 3 End NTFS Start Sector Offset NTFS Size NTFS End

720824544 1269536 722094080 722094080 0 254679040 976773120

The negative sector offset means the NTFS header is located somewhere in the current Recovery HD partition. This is the reason for asking if there are any additional files in '4' (because it may be a part of the NTFS partition you are looking for).

So you also need to execute 'd', '3'.

Jan 20, 2015 4:06 PM in response to Loner T

Loner T wrote:

If I correct the GPT3 start, see the comment below the table. You also need to delete GPT 3, not just GPT 4.

Using the start/end/size from '4' and '5', this is what the numbers look like...

GPT 3 Start GPT 3 Size GPT 3 End NTFS Start Sector Offset NTFS Size NTFS End

722036736 1269536 722094080 722036736 -57344 254734336 976771072

GPT 3 Start GPT 3 Size GPT 3 End NTFS Start Sector Offset NTFS Size NTFS End

720824544 1269536 722094080 722094080 0 254679040 976773120

The negative sector offset means the NTFS header is located somewhere in the current Recovery HD partition. This is the reason for asking if there are any additional files in '4' (because it may be a part of the NTFS partition you are looking for).

So you also need to execute 'd', '3'.

ok, how can I cancel current action?

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Boot camp lost after upgrading to Yosemite from mountain lion