kemaltalen
Level 1
(0 points)
Q: My issue with bootcamp partition
Directed from the thread: Repairing Boot Camp after creating new partition.
Here's what happens when I type the "v" command:
Command (? for help): v
No problems found. 126900133 free sectors (60.5 GiB) available in 3
segments, the largest of which is 126899792 (60.5 GiB) in size.
The problem (I believe) started when I resized my partitions using MiniPartition Tool Wizard. I am not rebuking this program, because I'm sure it has worked for many others. However, this in combination with resizing my Macintosh HD using disk utility might have proliferated the problem. I have taken these steps:
1. Downloaded and installed GTP gdisk
2. Wrote partition 4 (BootCamp) to a MBR hybrid with EFI System Partition on top
Currently: I can see my bootcamp drive at startup, but when I boot into Windows 7, the OS is not found.
Christopher Murphy
Level 3
(555 points)
So the event and problem it caused in order looks like:
1. Disk Utility permits modification of the partition layout on a drive with a hybrid MBR in violation of this technote. Specifically "If block 0 contains any other form of MBR, it should refuse to manipulate the disk." This fools the user into thinking such a resize operation is sanctioned.
2. MiniPartition Tool, like Windows when booted on BIOS systems (including Apple hardware), only honors the MBR, while ignoring the GPT. It resizes Windows successfully but only updates the MBR. This doesn't cause an immediate Windows problem because Windows uses only the MBR, which is correct for Windows, and OS X only uses the GPT which is correct for OS X. The only noticeable problem that occurs is that the Windows volume no longer mounts in OS X because the GPT partition for it is incorrect.
3. Using Disk Utility again has two problems. First since it shows the stale GPT it can actually permit you to resize the OS X volume in a way that overwrites part of the Windows volume. Only if you shrank the OS X volume are you maybe in the clear for this problem. If it allowed you to increase the size of the OS X volume, you probably actually overwrote important file system information on the Windows volume, and recovering from this is in the realm of professional data recovery services. Second, it causes the correct partition information for Windows, stored in the MBR, to be removed in favor of the same (stale) information that was in the GPT.
So assuming your last Disk Utility resize was to shrink, testdisk should find the NTFS volume somewhere in the 62GB of free space (it's free space according to the GPT, obviously this is wrong). Because you've done multiple resizings, testdisk will likely find more than one candidate for a Windows volume. You'll need to use the option to list files to determine which candidate actually contains your files. Once you've found the correct candidate, you have two choices, testdisk can extract your files (to OS X) and then you can use Boot Camp Assistant to obliterate Windows, and reinstall it; or you can use gdisk to delete partition 4 (for Windows), create a new partition 4 plugging in the testdisk start and end sector values for the Windows volume, and reboot. If the values are correct, the OS X Finder will read-only mount the Windows volume and within OS X you'll be able to see your files. Next you'd use gdisk to create a new hybrid MBR similar to what you did before, but instead of just adding GPT #4, you should add 2 3 and 4 - only because that's how Apple does it and doing it their way will probably save you grief down the road.
Alternatively if you have backups for OS X and Windows, is to completely start from scratch: new OS X install, resize with Boot Camp Assistant, update OS X and restore from backup, reinstall Windows, restore Windows backup. This will take longer, but is the easiest to do.
