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inadvertently converted disk to dynamic: can't boot OSX or reinstall

327 Views 12 Replies Latest reply: Feb 2, 2013 1:02 AM by BoHick RSS
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Jan 29, 2013 7:29 PM

Greetings Folks,


I am on a mid-2012 MacBook Pro 13 that received a few days ago so first ever post on a Mac forum - hope it's as friendly and useful as the one over at Lenovo.


Just came back to Mac. Long story, boring details, but in addressing an 18-month old tantrum and in a Homer moment I was being inattentive and converted my HD to dynamic under Windows 7 while trying to convert a partition to exFAT for sharing files.


Like some noob fool I did not make recovery disks at the get go and the fact that there were no disks shipped with the machine didn't register as it should have (my only complaint regarding the product - the rest is ALL my bad). And no, also like some noob fool I did not, having seen it for the first time, tuck anything into Time Machine either. So it's the short and curlies for me...ah yes, and under Internet Recovery when I tried to access the installation and recovery option in Safari, it told me there is no machine registered under my name, something I thought was addressed when I first accessed updates and etc. from the AppStore.


To get on with it, I can't boot into OSX and I can't erase the HD uneder OSX Disk Utility either - I am in Viet Nam and internet is slow so everytime I resort to CMD R to get Internet Recovery it takes hours to load. Verify says the OSX Base Operating System is ok. Error messages I get:


"Couldn't modify partition map" when trying to erase the OSX partition for a reinstall of ML;


"Couldn't write installion information to disk" when trying to reinstall ML and no disk visible to select


From years dealing with Windoze I know that there's only a clean wipe and reinstall to go back to NTFS from dynamic, so I suspect I will have to completely wipe and reformat the HD. I already tried wiping the original partition under W7 but still can't get Disk Utility to do anything with it. So my question (assuming a fool is correct) is this:


What is the best tool to wipe and reformat the HD to something my MBP will then recognize and I can (go through the days it will likely take to download and) reinstall ML?


Or is there an easier, softer way? My Spidey Sense says no...



MacBook Pro, OS X Mountain Lion (10.8)
  • Kappy Level 10 Level 10 (221,035 points)

    Drive Preparation and Installation for Mountain Lion


    1.  Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button. Select Disk Utility from the main menu and click on the Continue button.


    2. After DU loads select your hard drive (this is the entry with the mfgr.'s ID and size) from the left side list. Note the SMART status of the drive in DU's status area.  If it does not say "Verified" then the drive is failing or has failed and will need replacing.  SMART info will not be reported  on external drives. Otherwise, click on the Partition tab in the DU main window.


    3. Under the Volume Scheme heading set the number of partitions from the drop down menu to one. Click on the Options button, set the partition scheme to GUID then click on the OK button. Set the format type to Mac OS Extended (Journaled.) Click on the Partition button and wait until the process has completed.


    4. Select the volume you just created (this is the sub-entry under the drive entry) from the left side list. Click on the Erase tab in the DU main window.


    5. Set the format type to Mac OS Extended (Journaled.) Click on the Security button, check the button for Zero Data and click on OK to return to the Erase window.


    6. Click on the Erase button. The format process can take up to several hours depending upon the drive size.

  • Imp68 Level 4 Level 4 (2,135 points)

    While booted into Internet Recovery, you should be able to repartition the drive.


    Select the drive itself >> partition on the right >> change current to 1 partion >> click option and check off guid partion table, click ok >> change name to something (Machintosh HD typically) >> format to Mac OS extended journaled >> apply.


    That should fix things and allow a fresh install.

  • Imp68 Level 4 Level 4 (2,135 points)

    Sorry my response was late after Kappy's.  I was typing it on my iPod haha.


    Just to note a thing about Kappy's response, it won't work entirely as described under normal circumstances.  In his response, you're booting straight off the recovery partition.  Since that partition is in use and locked, when you go to partition, you'll receive an error about not being able to unmount the drive.  Also, a couple terms sound like an older DU and won't match what you see.


    It sounds like your system is going straight to Internet Recovery anyway, though.

  • Imp68 Level 4 Level 4 (2,135 points)

    Oh, one other thing, steps 4 to 6 won't be necessary.

  • Imp68 Level 4 Level 4 (2,135 points)

    As it stands, you're not even booting off the hard drive to begin with.  You're booting into Internet recovery.  So wiping the drive won't matter.


    I find it really odd the drive can't be repartitioned.


    Just to recap, this should work:  From disk utilities, select the actual hard drive (this will be the one with the numbers: ex 500.11 GB etc).  Then click the partition tab on the right area.  Change the current layout to 1 partion, click options and be sure guid partition table is selected, format is set to Mac OS extended journaled, then apply.  When it's done, close du and then reinstall.


    This exact procedure doesn't work?

  • Imp68 Level 4 Level 4 (2,135 points)

    Glad it seems to finally be working.


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