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Missing operating system after MBR repair

Hi,

I have dual system on my mac book pro, windows on boot camp. I haven't been using windows for a while and when I tried to log back in recently, I found that I can't see windows after pressing 'alt' upon start up. I then searched here and found a solution to the problemRepairing boot camp after OS install 10.10.2. After the repair, I can now see windows during start up, but when I tried to boot into it, it displays 'missing operating system...'. I then found another possible solution to the problem, which told me to try to use the startup repair option on windows disk to fix the problem. It did not work. Hope I can get some help on here. Thanks.

@Kappy

Yang

Posted on Feb 24, 2015 1:06 PM

34 replies

aurthes Author

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Feb 25, 2015 2:46 PM in response to Loner T

1 . I did use EFI/GPT.

2. So you mean the 5 entries displayed are all problematic and cannot be repaired?

3. Here's my deep search result:

aurthes Author

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Feb 25, 2015 2:48 PM in response to Loner T

and I came back to analysis and I got this:

Loner T

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Feb 25, 2015 3:01 PM in response to aurthes

Here is a table based on your Deeper Search.

GPT 3 Start	GPT 3 Size	GPT 3 End	NTFS Start	Sector Offset	NTFS Size	NTFS End
292241760	1269536	293511296	292448256	-1063040	684654592	977102848

The negative Sector Offset is not a good sign. Using 512-byte sectors, the sector offset is roughly 519MB. The Recovery HD - GPT 3 is 650MB, so you will lose Recovery HD, but this entry makes the most sense.

If you press Enter on the screen which had the [BOOTCAMP] entry, the Deeper Scan needs to be restarted. Once you get to the list which has the following entry, do not press enter, but use up/down arrow keys to get to this entry and then use 'P - List Files'. We need to see what files are in this entry.

aurthes Author

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Feb 26, 2015 6:34 AM in response to Loner T

If there's no significant downside on losing recovery HD, I think I'll be fine with it. All I care is my macintosh and boot camp.

I ran deep search again overnight, and here are the files in the BC entry you mentioned:

Loner T

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Feb 26, 2015 6:54 AM in response to aurthes

Do you recall if you installed Windows using EFI or a regular Bootcamp Windows installation? What year/model is your Mac?

aurthes Author

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Feb 26, 2015 2:26 PM in response to Loner T

1. I do not recall that, but I would assume that I used regular bootcamp windows installation.

Loner T

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Feb 26, 2015 10:42 AM in response to aurthes

You may not want to post Serial Numbers on a public forum. In the screen shot you have, are there any more files?

aurthes Author

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Feb 26, 2015 11:57 AM in response to Loner T

You mean the Bootcamp entry? No

aurthes Author

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Feb 26, 2015 12:08 PM in response to Loner T

I cannot believe posts are only allowed to be edited in the first 15 mins. I cannot even edit my previous post now. There goes my sequence number.

Loner T

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Feb 26, 2015 2:19 PM in response to aurthes

I will try and ask the hosts to remove it.

aurthes Author

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Feb 27, 2015 5:03 AM in response to Loner T

Thanks. So what's the next step for me?

Loner T

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Feb 27, 2015 6:46 AM in response to aurthes

There is a sister tool to Testdisk, called PhotoRec. Do you want to look at that for extracting Windows files? How averse are you to losing Windows?

aurthes Author

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Feb 27, 2015 7:47 AM in response to Loner T

I take it as my windows is hard or impossible to recover? I only care about the files in windows. Can you walk me through how to extract files? Thanks.

Loner T

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Feb 27, 2015 8:23 AM in response to aurthes

If Testdisk cannot locate a valid NTFS partition, try PhotoRec - http://www.cgsecurity.org/wiki/PhotoRec.

aurthes Author

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Feb 28, 2015 10:09 AM in response to Loner T

So from the current results of testdisk, we are not able to locate NFTS partition?

Can you walk me through how to extract windows file with PhotoRec?

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Missing operating system after MBR repair