After updating to Maverick, Windows 7 bootcamp partition can't mount

My situation was identical to the that of the following post:

Re: Can't access Bootcamp after partition

So I followed Chris' posted instructions and ended up with the required "*4: 07" (see below, computer name removed). I've rebooted but the partition is still appearing as "disk0s4" in its greyed out state in disk utility. Still not getting the option to boot into Windows 7 when I use the alt/option key.

Blair

Current view of the bootcamp partition in Disk Utility:

FYI, if it helps, this happened after installing Maverick to update my OS 10.6.8. I believe 750 GB is the correct size of the Windows 7 Bootcamp partition. I mention that because a lot of people with a similar issue seem to report the partition size being incorrect after the OS update. Hoping that's a good sign.

Posted on Aug 1, 2014 9:17 AM

72 replies

Aug 15, 2014 12:59 PM in response to Loner T

OK, so running the last suggested command, this is what I get. Not sure what to do now.

Aug 15, 2014 1:21 PM in response to blairoverthere

It's been sufficiently long I don't remember any of this and really don't want to read the thread from the beginning. I suggest starting from scratch with the current state of things. Use control-C to force quit that current instance of fdisk. And then:

sudo gpt -r -v show /dev/disk0

sudo fdisk /dev/disk0

Loner T

Level 9

59,536 points

Aug 15, 2014 1:38 PM in response to blairoverthere

@Christopher .. Testdisk start and end needs to be plugged in MBR entry 3.

@Blair see my post on Aug 3

Aug 15, 2014 1:55 PM in response to Christopher Murphy

Hi Chris, thank you for taking a look. Yes, sorry, I got as far as I could then had to travel away from home for a while. Here is the output from the two commands you just offered:

Aug 15, 2014 1:53 PM in response to Loner T

LonerT, you wrote:

sudo fdisk -e /dev/disk0

setpid edit 3

07

<Enter the correct start/end size to match the GPT>

flag 3

p

w

y

second line is just "edit 3" right? and the <> you wrote should simply read 203046360? so like:

sudo fdisk -e /dev/disk0

edit 3

203046360

flag 3

Loner T

Level 9

59,536 points

Aug 15, 2014 2:53 PM in response to blairoverthere

You will need a start and size, but Testdisk provided start and end numbers.

size = end - start - 1

Plug in the appropriate values from Testdisk. Your GPT entry may also need to be corrected. The MBR update will allow testing windows. Mobile devices are a pain to type on.

Aug 15, 2014 5:48 PM in response to Loner T

OK well being lazy and not looking back through the thread, I don't know what's going on. But I'm still thinking whatever tesdisk's values are for partition 3 first need to be in the GPT because OS X only cares about the GPT. Then just create a new hybrid MBR from scratch. But it's 6 and 1/2 dozen...

Aug 19, 2014 6:54 AM in response to Loner T

Thank you guys so much for sticking with me through this. Here's what's currently showing in testdisk. So do I do something like:

sudo fdisk -e /dev/disk0

edit 3

203046360-1953520064 (don't know syntax here--re:beginning & end, size, etc?)

flag 3

And then modify the GPT somehow and create a new hybrid MBR and voila?

Loner T

Level 9

59,536 points

Aug 19, 2014 7:06 AM in response to blairoverthere

Look at the third column in the entry for he NTFS partition, which has 'size'. Use that.

We can defer the GPT correction and try to get this to work first.

The size entry for the disk I have is not valid, but here is an example (if you ignore the error).

sudo fdisk -e /dev/disk0

Password:

fdisk: could not open MBR file /usr/standalone/i386/boot0: No such file or directory

Enter 'help' for information

fdisk: 1> p

Disk: /dev/disk0 geometry: 31130/255/63 [500118192 sectors]

Offset: 0 Signature: 0xAA55

Starting Ending

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

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

1: EE 1023 254 63 - 1023 254 63 [ 1 - 500118191] <Unknown ID>

2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

3: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

fdisk: 1> edit 3

Starting Ending

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

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

3: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

Partition id ('0' to disable) [0 - FF]: [0] (? for help) 07

Do you wish to edit in CHS mode? [n]

Partition offset [0 - 500118192]: [0] 203046360

Partition size [1 - 297071832]: [297071832] 1750473705

'1750473705' is out of range.

Partition size [1 - 297071832]: [297071832]

fdisk:*1> p

Disk: /dev/disk0 geometry: 31130/255/63 [500118192 sectors]

Offset: 0 Signature: 0xAA55

Starting Ending

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

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

1: EE 1023 254 63 - 1023 254 63 [ 1 - 500118191] <Unknown ID>

2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

3: 07 1023 254 63 - 1023 254 63 [ 203046360 - 297071832] HPFS/QNX/AUX

4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

fdisk:*1> flag 3

Partition 3 marked active.

fdisk:*1> p

Disk: /dev/disk0 geometry: 31130/255/63 [500118192 sectors]

Offset: 0 Signature: 0xAA55

Starting Ending

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

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

1: EE 1023 254 63 - 1023 254 63 [ 1 - 500118191] <Unknown ID>

2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

*3: 07 1023 254 63 - 1023 254 63 [ 203046360 - 297071832] HPFS/QNX/AUX

4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

Aug 19, 2014 7:44 AM in response to Loner T

Love this, thank you! Done. Now just "w" and "y" to write it yes?

Loner T

Level 9

59,536 points

Aug 19, 2014 7:46 AM in response to blairoverthere

Yes, that is correct. Have your Windows DVD handy, in case a startup repair is needed. 😉

Aug 19, 2014 7:56 AM in response to Loner T

Got it. OK, this is what I got back from writing:

fdisk:*1> w

Device could not be accessed exclusively.

A reboot will be needed for changes to take effect. OK? [n] y

Writing MBR at offset 0.

fdisk: 1>

So now shutdown, reboot, and hold down option and hope that I can boot into windows? And then if I get a message like "Windows not found" or some such then do it again with the startup disk and try doing a standard repair (e.g., as opposed to bootrec.exe with it's various fixit parameters, e.g., /fixmbr, /fixboot, /scanos, /rebuildbcd)?

Aug 19, 2014 8:05 AM in response to blairoverthere

Yes. Windows Startup Repair might take a while. I've heard of it taking hours. If you're comfortable with bootrec.exe you could just go straight to that. Really, nothing should have touched it so you shouldn't even have to do this. But...

If you do try bootrec, do /fixmbr and /fixboot. It'll take about 2 seconds and then reboot to see if it worked. If not, then work through the rebuildbcd business.

Aug 19, 2014 8:14 AM in response to Christopher Murphy

OK, thanks. As a first step I tried to see if would simply boot into Windows and got the "Operating System Not Found" message in a DOS-sy type window. So, before attempting a repair, I just rebooted into the Mac OS to see if the partition was being recognized. It's still greyed out, is that to be expected? And it's also listed as FAT rather than NTFS. Fine or do I need to fix that first? If fine, I'll put in the Windows 7 repair CD I have and boot into that, get to the command prompt and run bootrec.exe with /fixmbr and then /fixboot. And then do a regular fix if that doesn't work. Sound right?

Loner T

Level 9

59,536 points

Aug 19, 2014 8:25 AM in response to blairoverthere

You should be able to complete startup repair and it should correctly show up in DU and Finder.

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After updating to Maverick, Windows 7 bootcamp partition can't mount