Upgrade vs. Clean Install

Discussion in 'OS X Mountain Lion (10.8)' started by Lihi, Aug 19, 2012.

  1. Lihi macrumors newbie

    Nov 13, 2010
    I've searched through the forums and google and still didn't get my answer,
    so i would love your input.

    I own a 27" iMac, exactly 1 year old.
    I bought it just when lion was released, got it with snow leopard, on the first startup I downloaded my copy of lion and did a clean install (didn't want any old OS files to stay on my new machine).

    Now I want to install Mountain Lion, and i'm having a hard time deciding between an upgrade and a clean install. And if i'm doing a clean install, maybe it's best to restore everything manually? (don't see the point in restoring my whole disk image just like it was).

    I use my iMac on a daily basis, I have all my data backed up (time machine and a bootable disk image). Of course upgrading would be the easy way, but i don't mind spending time installing everything after a clean install - it that is indeed necessary.

    So will a clean install really make a big difference in performance for the long run? would love to know what you guys think. I just want mountain lion already :)
  2. GGJstudios macrumors Westmere


    May 16, 2008
  3. Lihi thread starter macrumors newbie

    Nov 13, 2010
    I've read the sticky, it has a great guide on HOW to make a clean install (which i already know), but didn't answer my questions about how will an upgrade or a clean install affect my workflow on my iMac, for the short and long run. As for the 2 other threads you posted - i am looking for a more detailed answer than just "upgrade"/"clean install".

    I'm trying to figure out if the clean install is worth the work of restore/installing everything or not.
  4. Badrottie Suspended


    May 8, 2011
    Los Angeles
    upgrade save my time and headache of re-installing apps over again. Run perfectly.
  5. robgendreau macrumors 68040

    Jul 13, 2008
    A "clean install" is completely unnecessary unless there's a good reason to erase and reformat your drive. It won't necessarily make ML faster or more efficient, but it can sometimes fix stuff that's broken (just like restarting can as well, although it's usually better to diagnose the problem). We challenged anyone to come up with data supported the fact that a "clean" installation was somehow preferable, and no one has risen to the occasion. Most people don't bother since it DEFINITELY is a slower way to upgrade. And make sure you keep what you need to keep; a clean install might result in eliminating old Apple stuff you might want to keep.

    If you have nothing to do, and want to manually reformat your drive and then reinstall everything by hand, it will probably work OK. There's always some risk associated with that, of course. Maybe you could do some benchmarking before and after and answer the question of whether it makes a difference. Apple doesn't seem to think so.
  6. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    This is kind of like religion around here. Some are firm believers in a fresh install with every update, and others don't really see the point.

    My experience has been if the machine is running okay now, it will work fine just going the upgrade route.
  7. SRLMJ23 macrumors 68000


    Jul 11, 2008
    New York
    I have a Late 2010 MacBook Air: I originally upgraded Lion to Mountain Lion and things were just not going well. A lot of lag, slow startup, glitches etc...

    So, I fresh installed Mountain Lion via USB stick I made and BAM, all the problems are gone and battery life is back to almost normal, which I am sure they will fix with the next update!

    My advice, Fresh Install ALWAYS!
  8. 49JC macrumors member

    Jul 11, 2010
    Not sure bout how worth it it is for clean install vs upgrade. But I do know I was having the longest time with an issue of my mbp not playing netflix because of silverlight. I went thru every article out there to fix this issue (reinstall, uninstall, delete files, etc) with no luck. Ran a clean install on a new SSD i bought and was able to install the required silverlight and everything ran fine. So yes im sure it fixes a few things doing clean install. :D
  9. Lihi thread starter macrumors newbie

    Nov 13, 2010
    First of all thank you all for the replies. I think I'll go with the upgrade (changed my mind due to this thread, i was already preparing for a clean install). I've been keeping my iMac in a good health during its first year, and i'm pleased with the way it's running so i'll just upgrade for now.

    Just curious, what's the risk in a clean install? Wiping the disk may damage it?
  10. itickings macrumors 6502a


    Apr 14, 2007
    No, if the disk is damaged by that, it was already faulty and about to die soon anyway.

    The main risk is that you wipe the disk without sufficient backup and lose data. I read about one poor soul that had an encrypted Time Machine backup and didn't realize it until after having wiped the keys, losing everything. I have at least one bootable clone and an accessible Time Machine backup to revert to should something fail.

    I for one always opt for clean installs, not because I don't trust the upgrade, but because I take it as an opportunity to get organized and completely wipe out unused software, settings and other data. Spring cleaning :p
  11. Icaras macrumors 603


    Mar 18, 2008
    California, United States
    Same here. Mountain Lion was my first ever non-clean install OS upgrade and I finally came to the realization that I'm not dealing with Windows when it comes to installs.

    No issues. Couldn't be happier. In the future I will continue to do only upgrades.

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