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Resize Partion help


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After playing with OS X, I really love it and now want to give more space to my OS X partition. I found the command line directions to do this on macworld.com



I can't run the command and get an error. The directions say it has to be a GUID HFS+ partition. I checked with Didk Utility and mine is MBR HFS+.


My question is:

Is it safe to change the partition scheme from MBR to GUID?


Will I loose data? Will it still boot (I use Acronis)?


Or, is there another way to increase the partition size?

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I don't know the answer to your question, but I suggest caution. Remember, you are NOT running a Mac - you have a Hackintosh. And, for instance, it needs a special MBR (master boot record) style partition so the BIOS can boot it. This is not the only difference you will encounter. Again - be cautious...



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check this:




this is all i tried so far but well, none of the things i tried worked out to ->my


what does work though (you need some backup space somewhere else, preferably take some other hfs+-partition on a different drive)...


oh, and the way i'm walking here is probably way too much for 'the mean beginner'. sorry... could probably even write a little stand-alone-app for doing all of this from within apples own installer but i just don't feel like it. time's always a rare kinda thing...


*) start your favourite osX86-install-cd

*) launch the disk-utility from within the installer and make sure all the volumes you need for this operation are mounted (osX86-source and destination for the backup). of course, you can always mount volumes by using the terminal, too - whatever way you prefer)

*) launch the terminal application

*) cd /Volumes/[the_name_of_your_backup_volume]

**) do a 'ls /Volumes' if you're not sure...

*) tar -cvp /Volumes/[the_name_of_your_osX86_volume]/* ./backup.tar

**) in case you don't have as much space available as me for the backup (1:1) add a '-z' to compress everything abit. of course, it'll take a bit longer then

*) when done, 'cd /Volumes'

*) go back to the disk-utility and repartition the drive as needed

*) use fdisk (osx-terminal, linux, knoppix, dos/windows,...) to make sure that the active-flag (boot-flag) for the osX86-boot-partition is still is set (don't worry, the mbr stays all the way intact!)

*) again, make sure all volumes you need are mounted

*) back to the terminal, 'cd /Volumes/[the_name_of_your_osX86_volume]'

*) tar xvp -

*) repair the filesystem permissions afterwards (diskutility)


now, the system is at least able to boot without any of the errors i've described in my previous post, but some system-related things got screwed up nevertheless. however, i could easily solve those problems by launching 'pacifist' (


of course, you have to overwrite quite a lot but if you backup at least your kernel-extensions (cp -R /System/Library/Extensions /to/somewhere/else) before doing this, i haven't had any trouble getting the system back to its original state (i.e. the state before repartitioning) again.


works fine for me but i'm curious if someone else might have found an easier way to accomplish the task of resizing a fdisk-scheme-partitioned-partition/drive without killing the formely installed base...




ps: oh, and to answer your question: 'Can I safley change from MBR to GUID?' No, you just won't be able to boot that system then.


pps: in case whatever i wrote here is useful to more than just 'you', maybe someone should move this topic to somewhere else or make it a sticky thread.

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Here's a pretty safe way to do it, but it involves needing another drive. If you make an image of your system with Ghost 12 and save it to a windows partition. Then you can safely resize (make bigger not smaller) your HFS+ partition which will destroy the data on the partition. But now you can use Ghost 12 again to restore the old image to the new partition. If you try to put a larger image onto a smaller partition, even though a lot of the image is unused space, it won't let you do it.


Of course the easier way is to install OSX onto a pen drive or small usb drive along with your favorite image software like superduper or copycatx. Then you can boot with your usb drive, save an image of your main osx partition to another partition on another disk, repartition your original partition and then re-install the old image. Sounds complicated but really very easy, I make and restore images all the time. This does preclude the fact that you at least an extra hard drive.

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