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Clean re-install

827 Views 10 Replies Latest reply: Mar 29, 2012 6:30 AM by Breznet RSS
MetallicAsh Level 1 Level 1 (0 points)
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Jul 26, 2011 9:55 AM

I downloaded and installed OS X Lion when it came out a few days ago and for the most part I love it.

The only thing is, a couple of programs don't seem to be working as I hoped.

I would like to do a clean install of OS X Lion as I kinda hoped that I'd have the option but either there wasn't or I just missed it.

Does anyone know if I do a can re-install of Lion?

  • Breznet Calculating status...
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    Jul 26, 2011 10:29 AM (in response to MetallicAsh)

    First: Go to the downloaded “Install Mac OS X” app that you downloaded via the Mac App Store, right click and select “Show Package Contents”.

    Next: Navigate to Contents -> SharedSupport. There you’ll find the dmg-file that you can burn to a DVD using Apple’s own Disk Utility.

    Here’s how you create an USB dongle version. I tried this and it did work (and was – as expected – much quicker to boot/install than the DVD). Be aware to double – okay, make it triple – check that you select the correct devices during the process. Warning: I’m not taking responsibility if you format your harddrive and lose important data. Make a backup first!

    First: Get an empty USB stick with more than 4 GBytes of capacity. (Mine had 8 GB.) Start Disk Utility, erase and format the USB stick. I used “Mac OS X Extended” format, but “Mac OS X Extended (Journaled)” should work as well.

    Next: Go to the Finder and drag InstallESD.dmg from there into the left hand pane of Disk Utility, then select it, go to Restore and drag the InstallESD.dmg into the Source field and your USB stick into the Destitination field.Click on “Restore” to start the process. It took about 10-15 minutes in the case of my USB stick, but you’ll see a nice progessbar during the process. When it’s finished, you should see the USB stick mounted on your desktop and the installation files in it.

    After all that’s done reboot your Mac and press+hold the Alt key after the startup sound. Keep it pressed until you see the bootmenu and select the USB drive to boot from. That’s it, you can install 10.7 now.

  • Thebestplacehere Level 3 Level 3 (700 points)
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    Jul 26, 2011 10:36 AM (in response to MetallicAsh)

    I am no sure if is that option because th eone that apple give holding option when restart is reinstall but i am no sure it do a clean install i think more it just install it like you already did.You can clean your system with the SL cd and after update the software get Lion from the mac app store,is no the only option i suposse but may the better?

  • thomas_r. Level 7 Level 7 (26,935 points)
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    Jul 26, 2011 10:39 AM (in response to MetallicAsh)

    Unfortunately, if you installed Lion without saving a copy of the installer, that's more difficult to do, since the installer self-deletes when finished.  (If you did keep a copy of the installer, create a Lion boot disk and use that to erase the hard drive and reinstall.)


    You'll need to reboot from your Mac OS X 10.6 install disk, use Disk Utility (from the Utilities menu) to erase the hard drive, then reinstall 10.6.  Then you'll need to use Software Update to install all the updates, so you can get up to 10.6.8, which is capable of installing Lion.  Then download Lion again, only this time keep the installer (copy it before installing) and make the boot disk referred to above.  Finally, let the installer run.


    Note that this extreme measure may not be necessary and may not help.  If the programs you're having trouble with are simply not compatible with Lion for some reason, they still won't work after a clean reinstall.  However, if you're heck-bent on doing it, you now have the power to do so...

  • Thebestplacehere Level 3 Level 3 (700 points)
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    Jul 26, 2011 10:42 AM (in response to MetallicAsh)

    Oh you can get the installer again just holding option when click purchase tab in the app store then installed change to install.

  • Breznet Level 1 Level 1 (25 points)
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    Jul 26, 2011 10:46 AM (in response to MetallicAsh)

    Another option is to upgrade to Lion then hold down option/alt on boot up and boot from the Restore partition and do a clean install from there.

  • thomas_r. Level 7 Level 7 (26,935 points)
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    Jul 26, 2011 10:46 AM (in response to Thebestplacehere)

    Good to know, I was not aware of that.  That simplifies things, since you wouldn't need to go through SL again.

  • jackiperezcastro Calculating status...
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    Mar 28, 2012 11:31 PM (in response to thomas_r.)

    Hi Thomas,

    Is it possible to upgrade to OS X Lion, but without erasing the hard drive, so I don't have to re-install the sofware I already have on my mac?

  • Breznet Level 1 Level 1 (25 points)
    Currently Being Moderated
    Mar 29, 2012 6:30 AM (in response to MetallicAsh)

    Of course it is. Just when it first was released there were a few bugs upgrading


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