Q: Lost bootcamp partition

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TreeRhino

Level 1 (0 points)

Q: Lost bootcamp partition

While attempting to resize my bootcamp partition (and then, deleting said partition) my previously working Windows partition will no longer show up on the startup disk selection screen. I have read through a few of the forums of similar problems but none of them are quite the same and with my knowledge I'm unable to decipher enough of it to connect the dots. I'm running El Capitan 10.11.2 iMac

I'm fairly certain more information will be required but I'm not sure exactly what commands to enter.

EDIT: The Windows partition DOES show up in the Startup Disk selection in System Preferences. What I meant above is that it does not show up while holding alt on restart.

iMac, OS X El Capitan (10.11.2), null

Posted on Dec 29, 2015 9:23 PM

I have this question too

Solved

Loner T

Level 7 (24,738 points)

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A:

Brain freeze on my part. . Your Windows installation is on disk1, not disk0.

Step B - Mark Windows MBR as bootable.

In OSX Terminal, run the following commands. Please ignore the i386 MBR error message, but not any others. The first command puts you inside the Fdisk utility. The subsequent commands are Fdisk commands (till you enter 'q').

sudo fdisk -e /dev/disk1

p

setpid 4

07

flag 4

p

w

y

q

Reboot and test.

Posted on Dec 31, 2015 8:21 AM

Q: Lost bootcamp partition

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by Loner T,

Loner T Dec 30, 2015 1:07 AM in response to TreeRhino
Level 7 (24,738 points)

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Dec 30, 2015 1:07 AM in response to TreeRhino

1. What year is your iMac?
2. Can you post the output of the following Terminal commands?

diskutil list
diskutil cs list
sudo gpt -vv -r show /dev/disk0
sudo fdisk /dev/disk0
sudo gpt -vv -r show /dev/disk1
sudo fdisk /dev/disk1

The "sudo" commands will prompt for your password, and it will not be echoed back. You may also see a warning about improper use of "sudo" and potential data loss due to "abuse" of the command.
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by TreeRhino,

TreeRhino Dec 30, 2015 8:01 AM in response to Loner T
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Dec 30, 2015 8:01 AM in response to Loner T

Hey Loner T,

My iMac is a late 2013. Here are the requested command outputs

diskutil list
diskutil cs list

sudo gpt -vv -r show /dev/disk0

sudo fdisk /dev/disk0

sudo gpt -vv -r show /dev/disk1
sudo fdisk /dev/disk1
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by Loner T,

Loner T Dec 30, 2015 8:04 AM in response to TreeRhino
Level 7 (24,738 points)

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Dec 30, 2015 8:04 AM in response to TreeRhino

Please post the output of

sudo dd if=/dev/rdisk1s4 count=1 2>/dev/null | hexdump -C
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by TreeRhino,

TreeRhino Dec 30, 2015 8:20 AM in response to Loner T
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Dec 30, 2015 8:20 AM in response to Loner T
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by TreeRhino,

TreeRhino Dec 30, 2015 9:32 PM in response to Loner T
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Dec 30, 2015 9:32 PM in response to Loner T

Is there an issue that you can spot? I'm considering a fresh windows install but of course trying to avoid it if possible.
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by Loner T,Helpful

Loner T Dec 31, 2015 8:04 AM in response to TreeRhino
Level 7 (24,738 points)

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Dec 31, 2015 8:04 AM in response to TreeRhino

I do not see a need to re-install yet.

Step A - Disable El Capitan temporarily (About System Integrity Protection on your Mac - Apple Support)

1. Boot into Local Recovery (Command+R).
2. Start Utilities -> Terminal.
3. Type csrutil disable in Terminal and press Enter/Return.
4. Type csrutil status.
5. Boot normally, and type csrutil status to confirm that all individual entries are still disabled.

Step B - Mark Windows MBR as bootable.

In OSX Terminal, run the following commands. Please ignore the i386 MBR error message, but not any others. The first command puts you inside the Fdisk utility. The subsequent commands are Fdisk commands (till you enter 'q').

sudo fdisk -e /dev/disk0
p
setpid 4
07
flag 4
p
w
y
q

Reboot and test.
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by TreeRhino,

TreeRhino Dec 31, 2015 8:11 AM in response to Loner T
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Dec 31, 2015 8:11 AM in response to Loner T

The problem persists.
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by TreeRhino,

TreeRhino Dec 31, 2015 8:43 AM in response to Loner T
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Dec 31, 2015 8:43 AM in response to Loner T

Bingo! Excellent work, thanks so much for the help.
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by Loner T,

Loner T Dec 31, 2015 9:35 AM in response to TreeRhino
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Dec 31, 2015 9:35 AM in response to TreeRhino

Please back up OSX, Windows and create a Windows System Restore point.
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Accepted Answer · Dec 31, 2015 8:21 AM

Loner T

Level 7 (24,738 points)

Safari

Dec 31, 2015 8:21 AM in response to TreeRhino

Brain freeze on my part. . Your Windows installation is on disk1, not disk0.

Step B - Mark Windows MBR as bootable.

In OSX Terminal, run the following commands. Please ignore the i386 MBR error message, but not any others. The first command puts you inside the Fdisk utility. The subsequent commands are Fdisk commands (till you enter 'q').

sudo fdisk -e /dev/disk1

p

setpid 4

07

flag 4

p

w

y

q

Reboot and test.

Q: Lost bootcamp partition

All replies Helpful answers

by Loner T,

by TreeRhino,

by Loner T,

by TreeRhino,

by TreeRhino,

by Loner T,★Helpful

by TreeRhino,

by Loner T,Solvedanswer

by TreeRhino,

by Loner T,

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Helpful answers

by Loner T,Helpful