reinstalling yosemite

Discussion in 'macOS' started by nicolasleFada, Sep 10, 2015.

  1. nicolasleFada macrumors newbie

    Sep 2, 2015

    I have mac book pro running yosemite and i would like to reinstall it because some systems applications mainly utilities are not working after some removal by cleaning software....

    The situation is like this:

    1/ I bought this second hand and don't have install disc

    2/ cannot back up the OS bcoz is now weird and not really efficient

    3/ but i own also a imac with Lion as OS that is working perfectly

    So can anybody tell me the best way to proceed as by myself i was thinking of erasing all Yosemite and may be installing the Lion system and may be upgrading it later

    I am doing this kind of operation for the first time so if you could be clear it would be very kind and helpful.

  2. DeltaMac macrumors G3


    Jul 30, 2003
    If you can tell us more about which MacBook Pro you have, then we can tell you if it's possible to do what you are asking.
    Go to the Apple menu, then click About this Mac.
    That will tell you what CPU you have. It will also tell you which model you have, such as MacBook Pro (Late 2008), or whatever that shows. You can then click on the System Report button in that window. The Hardware Overview will also give you some more information.

    The reason that you don't have an installer disk, is that Apple only uses downloads for the OS install. No DVD disks for more than 4 years now.
    If you want to reinstall Yosemite, you can download the installer through the App Store. Save the installer before you let it run, and make a bootable installer drive. An 8GB USB flash drive is ideal for that. Then, you don't need to download all the installer files when you reinstall next time.
  3. nicolasleFada thread starter macrumors newbie

    Sep 2, 2015

    OK thanks for quick reply
    Mac model is :
    Apple MacBook Pro "Core i5" 2.3 13" Early 2011

    One more thing that can be useful is that my internet connexion is very low ....

  4. nicolasleFada thread starter macrumors newbie

    Sep 2, 2015

    Sorry but it takes me time to put up things together sometimes; but it came to my mind that it might be possible to plug the imac to the macbook and transfer from here to there.....
    is my idea stupid or make it sense?
  5. hallux macrumors 68030


    Apr 25, 2012
    This would be target disk mode -

    It's not a stupid idea.

    Also, if your Mac has the recovery partition on it, you can do a reinstall of the OS without data loss by booting to that recovery. Your Mac should support Internet Recovery, this would allow you to (slowly) reinstall the OS.
  6. Weaselboy Moderator


    Staff Member

    Jan 23, 2005
    There is really no reason to go back to Lion to fix this. Just reinstall Yosemite without erasing anything and it will replace the missing files and should fix this.

    First go to the App Store app and login with your AppleID then click > here to "purchase" the free Yosemite OS. Once the download completes just go ahead and run the installer (it should auto launch). That will reinstall Yosemite over top of the existing install and fix the missing files.

    This will not erase your data, but you should do a backup first just to be safe.
  7. DeltaMac macrumors G3


    Jul 30, 2003
    Any of the options that you might have to reinstall, including going back to Lion - or staying with Yosemite, and simply doing a reinstall - or using the Internet Recovery option - All would mean that you have to download something, Lion will be the smallest, less than 4GB. Yosemite files download to reinstall would be nearly 6GB. Large downloads - and a slow connection would be painful. Do you have ANY option of going somewhere that has a faster connection? (and a place that would allow you to download that much at one sitting :D )
    I think your best option is to stay with Yosemite, and just get that reinstalled. You might like to find a faster connection somewhere :cool:

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