Fixing missing Bootcamp partition after Mavericks rewrote wrong GPT

It should be OK to run Windows startup repair. Because OS X Finder mounts the Windows volume read only, that's a bit safer, so I'd sooner do that and get at least the most important data backedup before repairing Windows.

In one of your posts you mention using a VM instead of bootcamp and dual booting. What are the downsides of using a VM? Will both OS X and Windows run with less resources (RAM is my main concern).

My disk seems to be a little different. No Darwin Boot.

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 1023 254 63 - 1023 254 63 [ 1 - 409639] <Unknown ID>

2: AF 1023 254 63 - 1023 254 63 [ 409640 - 585937496] HFS+

3: 0C 1023 254 63 - 1023 254 63 [ 898164736 - 78608384] Win95 FAT32L

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

sudo gpt -r -vv show /dev/rdisk0

gpt show: /dev/rdisk0: mediasize=500107862016; sectorsize=512; blocks=976773168

gpt show: /dev/rdisk0: Suspicious MBR at sector 0

gpt show: /dev/rdisk0: Pri GPT at sector 1

gpt show: /dev/rdisk0: 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 585937496 2 GPT part - 48465300-0000-11AA-AA11-00306543ECAC

586347136 311817600

898164736 78608384 3 GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7

976773120 15

976773135 32 Sec GPT table

976773167 1 Sec GPT header

Do I need to add a new partition? What start sector would I use? 586347136? And what size? 311817600? Or do I need to use testdisk to get that information? If so, what options to that command? I think partition is really the Recovery HD.

Any help is greatly appreciated!

VMs have no access to true hardware but can do some limited driver stuff, but can run Guest OS (Windows) and Host OS (OS X) simultaneously. VMs usually are heavy on batteries and memory, but can avoid the specific issue of Bootcamp implementation on OS X (MBR and CSM-BIOS vs UEFI).

VM engines can let you boot bootcamp partition as a VM, which can be an appealing solution. Moving VMs to newer HW is easier than moving Bootcamp. VM engines can let you migrate between different engines (for example, VirtualBox to Fusion, or back).

It depends on what you want to achieve with either approach.

You do not have Windows bootable. fdisk entry #3 should be id 07 and flagged as bootable. (See man fdisk and look at option -e). Did your Bootcamp installation ever work?

Typically, you should have 4 partitions in MBR.

What events caused this state?

Created bootcamp. Later resized the OS X and bootcamp partitions. Everything was working fine up to this point. Installed Maverics. Restored 10.8.5 from Time Machine backup.

For 10.6 and older it's normal to not have a Darwin Boot partition. The layout suggests that Disk Utility was used to shrink the OS X volume. Use fdisk to change the MBR #3 type code to 07 and make it bootable. The fdisk commands to use for that are setpid and flag, use help to get more information.

Then backup OS X and Windows from their respective environments. The use diskutil resize (use man diskutil to learn how) to grow the OS X volume to use the space from the shrink you did. Now you'll have to fix the MBR yet again since diskutil removes this information due to a long standing OS X bug. And finally if you really want OS X smaller you should use someting like Camptune or Winclone or iPartition to adjust the relative sizes of these two partitions since Apple does not provide tools to do this. Otherwise, use Boot Camp Assistant to blow away Windows, and then use it to resize the drive the way you really want it, reinstall Windows from scratch with install media, and then restore your user data from backups.

What broke it was the Mavericks installer, which found that the MBR and GPT weren't synced because you did the resize with an unsupported utility that doesn't understand Boot Camp layouts. The installer, upon seeing the unsync'd MBR and GPT wrongly decides to fix it for you, an in so doing it causes Windows to no longer be bootable.

So anyway, I suggest you make a decision on what you want this to look like because at the moment it seems like you're not certain what OS you even want to be running let alone what you want the partition layout to be. Once you have a stable decision, and express it, then it'll be easier to tell you how to achieve it.

The installation I had was working fine for me 300GB OS X and the rest BOOTCAMP (Windows 7). Thought upgrading to Maverics would be simple.

I was asking about VM because I thought about going that route when I first set this up almost 2 years ago, but thought Windows would run too slow or be limited in RAM. So I went the BOOTCAMP route, but I made the disk too small ...

Well unfortunately Apple doesn't follow its own advice by disallowing Disk Utility to modify the GPT once a hybrid MBR has been created. They should only permit complete obliteration of all contents of a drive rather than allowing the perception of safe resizing. The trap you ran into is that the MBR described the disk one way, the GPT another way, but each permitted Windows and OS X to boot OK. But then when the Mavericks installer ran, it detected the difference and incorrectly assumed that they needed to be the same. On top of the mistake of modifying it at all, it "fixed" it wrong in two ways: did not set the active flag, it did not set the type code correctly. For some people it's a strike three when it deletes valuable information about the true Windows partition start sector in favor of the wrong (stale) information in the GPT. And the thing is, this has been filed as a bug for a long time and they either don't understand it still or they don't care. So there you have it, it's really not a platform particularly friendly to running anything other than OS X, what can I say?

As for the VM route, yes you avoid these particular problems with partitions and such. You do run into performance limitations, but how noticable this is depends on what you're running. Games are usually a non-starter because they want a lot of memory and need full access to accellerated video (GPU acceleration) which is very limited through a virtual machine. If it's for accounting applications and such, you probably won't notice any performance degradation.

If you want to keep on using Boot Camp, just don't trust Disk Utility to be of much help. And make regular backups of both environments because unless you have esoteric knowledge, it's a flaky arrangement that as you've experienced can blow up on you doing seemingly safe things like an OS ugprade that has nothing at all whatsoever to do with Windows.

So if I change the id of partition 3 to "07" and make it bootable what are the chances I can get back what I had before?

Then your suggestion is to back everything up and start over. I think I tried starting over before. On Windows I tried making a disk image and restoring that, but it just gave me back the same size partition.

Obviously I don't know what I'm doing. You suggested that I could do this with Camptune or Winclone or iPartition. I don't mind restoring my user data, but all the programs and settings is a real hassle.

If you change the MBR #3 partition to ID 07 and set the boot flag there's every reason to believe Windows will be bootable. Sometimes it's necessary to repair Windows with Windows Startup Repair afterward.

Setting partition 3 to "07" and making it bootable did allow it to show up as a bootable drive on system restart with the option key held down, but instead of booting it said "Press Ctrl-Alt-Del".

I decided to try testdisk "analyze" to see what it thought about my disk. It wasn't too happy. Even "Quick Search" took a long time.

TestDisk 6.14, Data Recovery Utility, July 2013

Disk /dev/disk0 - 500 GB / 465 GiB - 976773168 sectors (RO)

The harddisk (500 GB / 465 GiB) seems too small! (< 700 GB / 651 GiB)

Check the harddisk size: HD jumpers settings, BIOS detection...

The following partitions can't be recovered:

Partition Start End Size in sectors

> MS Data 966160592 1044768975 78608384

MS Data 976773112 1367197680 390424569

MS Data 976773119 1055381502 78608384

Mac HFS 976773124 978042659 1269536

I also got these messages.

Warning: number of heads/cylinder mismatches 255 (NTFS) != 1 (HD)

Warning: number of sectors per track mismatches 63 (NTFS) != 1 (HD)

and trying to look for files I got this for all NTFS partitions

Can't open filesystem. Filesystem seems damaged.

So it looks like deleting boot camp and starting over is in order.

No one suggested you use Test Disk. It wasn't indicated for your problem. I said your next step if the partition fixing didn't work was to use Windows Startup Repair, not Test Disk. There's no evidence or motive for the Mavericks installer to read or write within the Boot Camp partition. It would have to write inside that partition to damage the file system. If that's really happening, it's a whole different category of data loss.

When you boot OS X does the Boot Camp volume automount? Can you see it in the Finder, and can you navigate it and find folders and files on it? If so, it's not damaged. Run Windows Startup Repair.