Bootcamp partition will not boot

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niall_mc Author

Level 1

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Bootcamp partition will not boot

hi there,

I am having an issue with my bootcamp partition on my MacBook.

The windows partition is showing up when I hold down the Option key on startup but it just brings a cursor saying:

A disk Read error occurred.

Press Ctrl+Alt+Del

When I boot into Mac OS X the partition and check Disk Utility the windows partition is greyed out and showing up as disk0s4

From reading other solutions on this site I thought it may be the GPT and the MBr but I am unsure how to fix it.

The results of my fdisk and gpt checks are:

sudo fdisk /dev/disk0

Disk: /dev/disk0 geometry: 60801/255/63 [976773168 sectors]

Signature: 0xAA55

Starting Ending

#: id cyl hd sec - cyl hd sec [ start - size]

------------------------------------------------------------------------

1: EE 0 0 2 - 25 127 14 [ 1 - 409639] <Unknown ID>

2: AF 25 127 15 - 1023 254 63 [ 409640 - 388671872] HFS+

3: AB 1023 254 63 - 1023 254 63 [ 389081512 - 1269536] Darwin Boot

*4: 07 1023 254 63 - 1023 254 63 [ 390352896 - 586420224] HPFS/QNX/AUX

sudo gpt -r -vv show disk0

Password:

gpt show: disk0: mediasize=500107862016; sectorsize=512; blocks=976773168

gpt show: disk0: Suspicious MBR at sector 0

gpt show: disk0: Pri GPT at sector 1

gpt show: disk0: Sec GPT at sector 976773167

start size index contents

0 1 MBR

1 1 Pri GPT header

2 32 Pri GPT table

34 6

40 409600 1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B

409640 388671872 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

389081512 1269536 3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC

390351048 1848

390352896 586420224 4 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

976773120 15

976773135 32 Sec GPT table

976773167 1 Sec GPT header

Any help would be appreciated.

MacBook Pro, Mac OS X (10.7.4)

Posted on Oct 7, 2015 11:11 PM

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Answer 1

Best reply

Loner T

Level 9

59,471 points

Oct 8, 2015 3:26 PM in response to niall_mc

Please post the output of

sudo dd if=/dev/rdisk0s4 count=1 2>/dev/null | hexdump -C

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Answer 2

niall_mc Author

Level 1

0 points

Oct 8, 2015 3:29 PM in response to Loner T

Hi Loner T,

Sorry about the delay in getting back to you - had issues using the forum.

Here is the output of the command:

$ sudo dd if=/dev/rdisk0s4 count=1 2>/dev/null | hexdump -C

Password:

00000000 eb 52 90 4e 54 46 53 20 20 20 20 00 02 08 00 00 |.R.NTFS .....|

00000010 00 00 00 00 00 f8 00 00 3f 00 ff 00 00 50 44 17 |........?....PD.|

00000020 00 00 00 00 80 00 80 00 ff 07 f4 22 00 00 00 00 |..........."....|

00000030 00 00 0c 00 00 00 00 00 02 00 00 00 00 00 00 00 |................|

00000040 f6 00 00 00 01 00 00 00 0c 3b 7a fa 48 7a fa 80 |.........;z.Hz..|

00000050 00 00 00 00 fa 33 c0 8e d0 bc 00 7c fb 68 c0 07 |.....3.....|.h..|

00000060 1f 1e 68 66 00 cb 88 16 0e 00 66 81 3e 03 00 4e |..hf......f.>..N|

00000070 54 46 53 75 15 b4 41 bb aa 55 cd 13 72 0c 81 fb |TFSu..A..U..r...|

00000080 55 aa 75 06 f7 c1 01 00 75 03 e9 dd 00 1e 83 ec |U.u.....u.......|

00000090 18 68 1a 00 b4 48 8a 16 0e 00 8b f4 16 1f cd 13 |.h...H..........|

000000a0 9f 83 c4 18 9e 58 1f 72 e1 3b 06 0b 00 75 db a3 |.....X.r.;...u..|

000000b0 0f 00 c1 2e 0f 00 04 1e 5a 33 db b9 00 20 2b c8 |........Z3... +.|

000000c0 66 ff 06 11 00 03 16 0f 00 8e c2 ff 06 16 00 e8 |f...............|

000000d0 4b 00 2b c8 77 ef b8 00 bb cd 1a 66 23 c0 75 2d |K.+.w......f#.u-|

000000e0 66 81 fb 54 43 50 41 75 24 81 f9 02 01 72 1e 16 |f..TCPAu$....r..|

000000f0 68 07 bb 16 68 70 0e 16 68 09 00 66 53 66 53 66 |h...hp..h..fSfSf|

00000100 55 16 16 16 68 b8 01 66 61 0e 07 cd 1a 33 c0 bf |U...h..fa....3..|

00000110 28 10 b9 d8 0f fc f3 aa e9 5f 01 90 90 66 60 1e |(........_...f`.|

00000120 06 66 a1 11 00 66 03 06 1c 00 1e 66 68 00 00 00 |.f...f.....fh...|

00000130 00 66 50 06 53 68 01 00 68 10 00 b4 42 8a 16 0e |.fP.Sh..h...B...|

00000140 00 16 1f 8b f4 cd 13 66 59 5b 5a 66 59 66 59 1f |.......fY[ZfYfY.|

00000150 0f 82 16 00 66 ff 06 11 00 03 16 0f 00 8e c2 ff |....f...........|

00000160 0e 16 00 75 bc 07 1f 66 61 c3 a0 f8 01 e8 09 00 |...u...fa.......|

00000170 a0 fb 01 e8 03 00 f4 eb fd b4 01 8b f0 ac 3c 00 |..............<.|

00000180 74 09 b4 0e bb 07 00 cd 10 eb f2 c3 0d 0a 41 20 |t.............A |

00000190 64 69 73 6b 20 72 65 61 64 20 65 72 72 6f 72 20 |disk read error |

000001a0 6f 63 63 75 72 72 65 64 00 0d 0a 42 4f 4f 54 4d |occurred...BOOTM|

000001b0 47 52 20 69 73 20 6d 69 73 73 69 6e 67 00 0d 0a |GR is missing...|

000001c0 42 4f 4f 54 4d 47 52 20 69 73 20 63 6f 6d 70 72 |BOOTMGR is compr|

000001d0 65 73 73 65 64 00 0d 0a 50 72 65 73 73 20 43 74 |essed...Press Ct|

000001e0 72 6c 2b 41 6c 74 2b 44 65 6c 20 74 6f 20 72 65 |rl+Alt+Del to re|

000001f0 73 74 61 72 74 0d 0a 00 8c a9 be d6 00 00 55 aa |start.........U.|

00000200

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Answer 3

Loner T

Level 9

59,471 points

Oct 8, 2015 4:33 PM in response to niall_mc

Do you have any third-party NTFS or HFS software or Parallels?

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Answer 4

niall_mc Author

Level 1

0 points

Oct 8, 2015 4:56 PM in response to Loner T

I do not believe that there is any third-party NTFS or HFS software installed (other family members also use the machine)

There definitely is no Parallels installed.

The machine is primarily used just as a Windows machine and was rarely booted into OS X environment before the boot issue arose.

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Answer 5

Loner T

Level 9

59,471 points

Oct 8, 2015 5:07 PM in response to niall_mc

When did the problems start? Can you recall any significant events prior to it misbehaving?

Can you post the output of

diskutil list

diskutil cs list

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Answer 6

niall_mc Author

Level 1

0 points

Oct 8, 2015 5:19 PM in response to Loner T

The problem started about 2 weeks ago while my brother was using it and it has not booted into windows since. He is at work now so I have sent him an email to ask him what was happening with it before it stopped working. I will post his reply as soon as I get it.

The results of the 2 commands are:

$ diskutil list

/dev/disk0

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *500.1 GB disk0

1: EFI 209.7 MB disk0s1

2: Apple_HFS Macintosh HD 199.0 GB disk0s2

3: Apple_Boot Recovery HD 650.0 MB disk0s3

4: Microsoft Basic Data 300.2 GB disk0s4

$ diskutil cs list

No CoreStorage logical volume groups found

$

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Answer 7

Loner T

Level 9

59,471 points

Oct 8, 2015 5:22 PM in response to niall_mc

While you wait for email, can you check in Applications and see anything installed around the same time frame? Can you also check System Preferences for any non-Apple Preference Panes?

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Answer 8

niall_mc Author

Level 1

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Oct 8, 2015 5:32 PM in response to Loner T

I checked System Preferences and Applications and nothing looks like it has been touched - ever.

To be honest, I am not even sure he knows how to boot the machine into OS X mode and I use it almost exclusively in Windows mode as well.

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Answer 9

Loner T

Level 9

59,471 points

Oct 8, 2015 5:36 PM in response to niall_mc

Can you boot into Windows Safe Mode? Is Windows Automatic Update enabled?

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Answer 10

niall_mc Author

Level 1

0 points

Oct 8, 2015 5:49 PM in response to Loner T

When I try to load to Windows I just get a black screen with a flashing cursor before I get the error.

There does not seem to be any time to get it in to safe mode - I did try attaching an external keyboard and using the F8 button to get to Boot options but it just came up with the same error.

I previously tried to boot the machine from a Windows Installation disk so that i could repair the installation but the repair disk could not locate the Windows installation.

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