New OS requires starting from scratch?

Discussion in 'macOS' started by hakr, May 20, 2009.

  1. hakr macrumors regular

    Jan 18, 2009
    Western shore, Chesapeake Bay. Maryland
    In the Windoze world, from whence I came, the best way to upgrade from, say, XP Pro to VISTA, was to install the new OS onto a clean hard drive, not install over the old OS. Then you had to reinstall all your programs.

    Well, a new Mac OS is impending. Typically, how are these new OS's installed on an existing setup? It's new to me.
  2. Sky Blue Guest

    Sky Blue

    Jan 8, 2005
    You can do an upgrade or an archive and install. I usually do an erase and install.
  3. hakr thread starter macrumors regular

    Jan 18, 2009
    Western shore, Chesapeake Bay. Maryland

    When you say erase, I presume you mean erase the entire hard drive...and then you have to reinstall all your software again, right?
  4. Ivan P macrumors 68030

    Ivan P

    Jan 17, 2008
    Yes, that's what they mean. An erase and install writes the new OS over the current filesystem - the old OS and all it's contents are entirely erased; basically, you start from scratch.

    With an archive and install, it keeps all your settings, documents, etc., installs the new OS, and also creates an archive of the old file system that you can delete at a later date.
  5. AppleMatt macrumors 68000


    Mar 17, 2003
    I see where you're coming from...

    A clean install in both Windows and Mac = good.
    Re-installing all your programs, data etc = bad.

    'Archive and Install'

    Apple therefore created 'Archive and Install'. This installs a brand-new, clean version of the Mac OS to boot up and use, but it keeps all your user-data, programs etc untouched. The 'old' OS is put in a directory called 'System (old)', just in-case you need a file out of there. Once you've ascertained you don't you can just delete it.

    This is the best of both worlds IMO, you get all the benefits of an erase and install without all the hassle of actually having to do it.

    Tips for Clean Install
    If you want a clean install when upgrading from 10.5 > 10.6, then I recommend:
    1. Backup everything to an external drive.
    2. Upgrade your system first
    3. Boot up, and open all programs that contain databases, e.g. Mail, iCal etc.
    4. You'll notice very often between major versions Apple changes the format, so these programs will 'update' your user data to the new format.
    5. This is a good idea because when you do a clean-install and then restore your data, you aren't immediately cluttering it up by upgrading these. It's a minor benefit, but that's the whole purpose of a clean install anyway. Also it means if you have to grab a file from your backup drive at a later date, you don't have to worry about it being in the old format.

  6. ewilson6 macrumors 6502

    Nov 30, 2006
    when you erase and install it erases every program on your mac.

    a archive and install is the best way to go making sure that users and settings box is checkmarked. this will save all your users and settings.

    when you do an erase and install... you usually only have to enter the serial numbers on programs you bought.

    you shouldn't do an erase and install unless there is something wrong with OS X.

    In 24 years time I've only used archive and install about 10 times. I rarely have problems with Macs at all.
  7. Consultant macrumors G5


    Jun 27, 2007
    OSX is not windows.

    OSX has built in tool which makes it easy to migrate your apps and your user folder (documents, photos, music, etc.) to a new OS or new computer.
  8. Sun Baked macrumors G5

    Sun Baked

    May 19, 2002
    Apple has a sheet on the three options, which likely won't change for Snow Leopard.

    Mac OS X: About installation options

    1. Upgrade

    2. Archive and Install

    3. Erase and Install


    Unless you really like punching yourself in the face, the 3rd option is likely the last you want to do unless you get all your application install DVDs, the install keys, etc. before you start.

    Basically, turn off the login items and repair the drive before you do 1 or 2.

    Fun part about the 3rd option are those times when the new OS won't let you install the application and you have to wait for the company to release an updated installer. ;)
  9. crees! macrumors 68000


    Jun 14, 2003
    Gonna have to disagree with this statement which I figure is just a mistype. Erase and Install will erase the hard drive and you have the option to have it zero-out the drive as well.
  10. ewilson6 macrumors 6502

    Nov 30, 2006
    I edited my reply, was thinking of the preserve user settings dialog box on the startup dvd, so sorry!
  11. kostia macrumors regular

    Apr 14, 2007
    I always use the simple upgrade option and have NEVER had a problem. Yes, maybe it's "safer" (or cooler) to do archive and install or erase and install, but the trouble's not worth it. Upgrade works fine in the vast majority of cases, and for the vast majority of users (those who post here are a tiny minority).

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