Clean install.. Possible?

Discussion in 'OS X Mountain Lion (10.8)' started by NinjahKitteh, Jul 10, 2012.

  1. NinjahKitteh macrumors newbie

    Joined:
    Jan 30, 2012
    #1
    Hey, so lately my mac has been slowing down a bit. My HD is almost full and I have a ton of crap on here I don't need. I was wondering if it was at all possible to install mountain lion when it comes out on a partition as a fresh install, then move the stuff from the lion OS that I want to keep. (It will act as my backup) then later remove the lion OS and give mountain lion my full hard drive? Basically my issue here is that I want to do a clean install of mountain lion, but I have no external harddrive or anything like that to back up my stuff. Any ideas? Thanks for the help.
     
  2. stiligFox macrumors 6502a

    stiligFox

    Joined:
    Apr 24, 2009
    Location:
    10.0.1.3
    #2
    That is what I would do: go into disk utility, and repartition your drive and add a second partition, about as large as you can make it, minus say 5gb to leave some wiggle room for Lion. Install ML on that, then copy your stuff over, and when you are done, delete your Lion partition.

    Now, that's the gist of it. If I was mor awake I'd get into more details. Hope that helps!
     
  3. Watabou, Jul 10, 2012
    Last edited: Jul 10, 2012

    Watabou macrumors 68040

    Watabou

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    #3

    This is similar to what I had to do for clean install of Lion. My DVD Drive is broken so I couldn't use it to burn any DVDs of Lion and I didn't have any external Hard drive except for a western digital HD that is quite wonky at times and disconnects randomly and causes OS X to fsck everytime it does that. I actually use it for time machine but it has crapped out on me several times and I don't really rely on it much. So I didn't want to rely on it to install Lion.

    Well anyways, here is what I did for Lion and what I plan to do for Mountain Lion. It is tedious so beware of that.

    1. Make a new partition of your internal HD by going to Disk Utility. Make that partition bigger than 12 GB just to be safe since we will need some of that space soon.
    2. Install Mountain Lion on the newly created partition.
    3. Once it finishes installing, boot up that partition by shutting down and holding the option key while restarting your mac and select the newly created partition.
    4. Now you will have Mountain Lion but you are not done yet. Open up Disk Utility and erase the "main" partition.
    5. Now since it's impossible to expand the newly created partition, we will want to download ML AGAIN and install it on the main partition that you just erased.
    6. Once installed, boot up the machine again, holding option and go to the main partition, erase the smaller 12 GB partition and finally, restore the HD to a single partition.
    7. Success, you now have a clean install of Mountain Lion and your hard drive has been restored to a single partition.

    Yes, I know this is very long but if you REALLY want a clean install and you do not have a DVD Drive, a USB stick, or a external HD, I strongly believe that this is the only way. I went this exact route with Lion. I had to download Lion twice from the Mac App Store, once to install it on the small partition and then a second time to actually install it on the main partition.

    Hope this helps. If anyone has any alternatives though, I'm listening because I'm thinking that I will have to go this route for Mountain Lion too since I want a clean install.
     
  4. NinjahKitteh thread starter macrumors newbie

    Joined:
    Jan 30, 2012
    #4

    Is there any way to back up data using this method or at least keep it? I have about 50GB of stuff that I am hoping to keep when I upgrade to ML. I can put it on a bunch of DVD's but that would be really tedious and time consuming
     
  5. Watabou macrumors 68040

    Watabou

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    #5
    Yes you can. Just make the partition bigger to fit your needs. For 50GB of space, just make a 60GB partition just to be safe (this partition will take a LONG time). And then after installing Mountain Lion on that partition, move over your stuff to that new partition and then erase that parition. After you install Mountain Lion on the main partition again, just move it over BEFORE you erase.

    But just be prepared to wait for a LONG time. Seriously, if I were you, I would just upgrade and not worry about the clean install.
     
  6. NinjahKitteh thread starter macrumors newbie

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    Jan 30, 2012
    #6

    How bad do you think it would be if I didn't do a clean install? I was told that it would make the OS a lot slower and stuff if I kept all the Lion files so I am not sure. The biggest thing I am worried about here is performance. I can probably easily spend a day deleting all the crap on my computer that I don't need, I just thought it would be better performance wise to do a full clean install.
     
  7. Watabou macrumors 68040

    Watabou

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    #7
    It definitely won't make your OS slower. Whoever told you that doesn't know anything. I actually upgraded Leopard to get Snow Leopard and I didn't notice a performance hit. I mean, Apple won't offer the upgrade option as the default if they know the transition will make your computer slower, will they? I think you will actually notice an increase in speed since people on here have been saying Apple fixed a lot of Lion problems.

    I want to clean install because I just want to start over again with only my music and documents folder, nothing else.
     
  8. RabidMacFan macrumors regular

    Joined:
    Jun 19, 2012
    Location:
    California
    #8
    Repartitioning the drive sounds way too complicated to me. I would get a 4+ GB flash drive to use for the Mountain Lion install. Apple released Lion Recovery Disk Assistant to do this for Lion, and could do the same for Mountain Lion. You can also do this yourself with Disk Utility if you want.

    Anyways, here are the steps to do a clean install:
    1. Copy your main drive to an external hard drive. This isn't really a "backup" drive since after the next step it will be your only copy of your files. Better do this twice to different drives just in case. Carbon Copy Cloner is free and works well for this.
    2. Erase your disk and perform a fresh install using the Mountain Lion installer on your flash drive
    3. Start moving things back from your external hard drives
     
  9. NinjahKitteh thread starter macrumors newbie

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    Jan 30, 2012
  10. robgendreau macrumors 68030

    Joined:
    Jul 13, 2008
    #10
    Watabou is right.

    What you seem to need to do is some housecleaning. If you are already running out of room then a bunch of partitioning-fu is not gonna help much since you're gonna need more space.

    Seems like a good time to buy some backup storage. Doing partition work without a backup is way too risky IMHO. Having a backup on another partition is better than none at all, but doing the partition itself involves risk. I mean seriously: you can get an external portable drive to cover that 50 GB for under $40. If your stuff isn't worth that much then I guess you could try any method since you're not risking much.

    You could also do some serious deleting on your existing drive and then install ML per the usual route. That's usually gonna work, and probably the safest route. But Apple stills recommends a backup.

    Rob
     

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