Is there a way to revert the chain boot with Windows 7 because my mac drive is now being detected as NTFS

[elijah]

Hello, Im just a newbie with Mac OSx86, I got a problem with my Mac OS X partition, after i did the chain boot command with windows 7 my mac drive is now being detected as NTFS, what i did was follow the bcdedit /copy {current} /d "Mac OSX" , set / {GUID} Path \Chain0, but i think I mistakenly set the Windows GUID instead of the Mac OS X GUID, then I restart the computer and it won't boot anymore; I created another partition and installed the Mac OS X again, and tried to see if I can recover my files on it but no luck because the previous Mac drive is now being detected as NTFS and unmountable. Please tell what to do because I got most of my impt stuffs on the mac drive. Thanks

[srs5694]

I'm not very familiar with bcdedit, so I don't know precisely what it did; however, my suspicion is that you've changed the partition type code on one of your disk partitions. You should be able to correct the problem with a low-level disk utility, such as fdisk (part of OS X) or my own gdisk. Use fdisk if the disk is a pure-MBR disk, gdisk if it's pure-GPT or a hybrid MBR/GPT disk. Consult the documentation for each to learn how to change the partition type code. (See here for the fdisk documentation; the main gdisk Web site includes documentation, or you can type "man gdisk" after installing it to read its man page.) Note that both fdisk and gdisk are text-mode tools that you launch from a Terminal program. Be sure to read and understand the documentation before you change your partitions; a mistake could make matters worse. I'm not all that familiar with OS X's version of fdisk, but with gdisk, you'd launch it on a disk, then use "p" to view the current partition layout, then use the "t" command to change the relevant partition's type code from 0700 to AF00, then write the changes with the "w" command.

[elijah]

I'm not very familiar with bcdedit, so I don't know precisely what it did; however, my suspicion is that you've changed the partition type code on one of your disk partitions. You should be able to correct the problem with a low-level disk utility, such as fdisk (part of OS X) or my own gdisk. Use fdisk if the disk is a pure-MBR disk, gdisk if it's pure-GPT or a hybrid MBR/GPT disk. Consult the documentation for each to learn how to change the partition type code. (See here for the fdisk documentation; the main gdisk Web site includes documentation, or you can type "man gdisk" after installing it to read its man page.) Note that both fdisk and gdisk are text-mode tools that you launch from a Terminal program. Be sure to read and understand the documentation before you change your partitions; a mistake could make matters worse. I'm not all that familiar with OS X's version of fdisk, but with gdisk, you'd launch it on a disk, then use "p" to view the current partition layout, then use the "t" command to change the relevant partition's type code from 0700 to AF00, then write the changes with the "w" command.

 

Ok thanks for giving me an idea, i will try as soon as i got home

[elijah]

I've tried to read the documentation that you provided but i still was having problem looking for the old Mac OS X GUID using fdisk can you please tell me how to show the list of partition with GUID thanks.

[srs5694]

The partition ID for an OS X partition on an MBR disk is 0xAF (that is, hexadecimal AF, or decimal 175). The equivalent ID on a GPT disk is a long GUID that's reported or entered in different ways depending on the utility you're using. In gdisk, it's AF00.

 

When using fdisk, you just type "fdisk /dev/disk0" to see the partitions on the first disk. As I say, I'm not extremely familiar with OS X's fdisk, so you should read the documentation to learn more. If you see a partition of type 0xEE, then that means the disk is a GPT disk (or a hybrid disk), and you should use gdisk or some other GPT-aware utility to edit it.

 

With gdisk, you can type "gdisk -l /dev/disk0" to see the partitions on the disk, or type "gdisk /dev/disk0" to edit it, whereupon "p" will show the current partitions, "t" will change a partition type (you'll be prompted for the partition and its type), "w" will write your changes to disk, and "q" will quit without saving your changes.