4 Replies Latest reply: Jun 30, 2012 3:17 AM by sn0wman
sn0wman Level 1 Level 1 (0 points)

I have a MacBook Pro which was originally supplied with OS X10.4.9. I have upgraded using disks purchased from the Apple store to 10.5 and subsequently 10.6. More recently I upgraded to 10.7 using the download from the online App Store. I would like to perform an Erase and Install to get rid of the 'dross' on my hard disk and may do this as part of the 10.8 upgrade although have yet decide whether to wait for this or not.

 

My question....when doing the erase and install, do I have to start from scratch by loading the original 10.4.9 OS X version or can I start at 10.7. If the latter how would I do this given that I don't have a disk as it was downloaded from the App Store?


MacBook Pro, Mac OS X (10.7.4), 2.4 GHz Intel Core 2 Duo
  • 1. Re: Clean up Hard Disk through Erase & Install
    Courcoul Level 6 Level 6 (11,470 points)

    When you upgraded to Lion, did the process include setting up the Lion Recovery Partition? In other words, can you boot in Lion Recovery Mode? That's the only way you can wipe the main Macintosh HD partition and reinstall Lion from scratch. Once booted in Recovery Mode, you can use its Disk Utility to erase the main partition and proceed with Lion install, ensuring that none of the "dross" remains.

     

    Since your Mac did not come with Lion preinstalled, it is not entitled to automatic Lion access. You will be required to log in/authenticate on the App Store prior to starting the download and install process.

     

    Search around, there is a way to save the installer prior to completing the task, thus avoiding having to download the monster again. It is 4GB in size and unless you have a blazing-fast connection, will take awhile to download. Once install is done, the installer is automatically erased.

  • 2. Re: Clean up Hard Disk through Erase & Install
    sn0wman Level 1 Level 1 (0 points)

    Thanks. I did a reboot and held down the Option/Alt key and the original Lion installation has created a Recovery HD option so will now look for instructions elsewhere on what to do.

  • 3. Re: Clean up Hard Disk through Erase & Install
    Courcoul Level 6 Level 6 (11,470 points)

    Try to get an external drive of at least 20GB in size to practice installing Lion and/or saving the model-specific installer. That way you won't be stuck up the creek without a paddle when doing your Mac's main drive.

     

    A few useful links and procedures from dear ole Prof. Kappy: https://discussions.apple.com/thread/3786371?tstart=0

  • 4. Re: Clean up Hard Disk through Erase & Install
    sn0wman Level 1 Level 1 (0 points)

    Thanks. I have now successfully erased my hard disk and reinstalled Lion, and also created a a recovery disk.