Possible to dual boot Mavericks and Yosemite?

Discussion in 'OS X Yosemite (10.10)' started by dj95, Apr 1, 2015.

  1. dj95 macrumors member

    Joined:
    Oct 25, 2011
    #1
    Hi everyone,

    I have a 2014 rMBP that shipped with Mavericks and has since been upgraded to Yosemite. Is it possible to run Mavericks on a second partition now that the system has been updated to Yosemite i.e. it won't mess up the boot system? I would try it myself but I would rather avoid messing the system up :p

    Thanks
     
  2. maflynn Moderator

    maflynn

    Staff Member

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    May 3, 2009
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    Boston
    #2
    Just partition into two drives and use a USB thumb drive with Mavericks on it. You should be able to install it.
     
  3. KALLT macrumors 601

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    Sep 23, 2008
    #3
    I still have Snow Leopard on an external drive and it works without problems.
     
  4. Taz Mangus macrumors 68040

    Taz Mangus

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    Mar 10, 2011
    #4
    Out of curiosity, if the OP were to create a new empty partition and boot to the recovery partition could they install Mavericks to the new partition? I know that when you reinstall from the recovery partition the OS that gets downloaded and installed is the same as what came installed with the computer when it was purchased.

    The other thing is unless the OP poster had a copy of Mavericks saved off somewhere they could not get it from the MAS any longer.
     
  5. Taz Mangus macrumors 68040

    Taz Mangus

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    Mar 10, 2011
    #5
    I highly doubt that Snow Leopard will even boot on a 2014 rMBP.
     
  6. Bruno09 macrumors 68020

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    #6
    Using the Recovery partition (Cmd + r) installs the current OS. (here, Yosemite)

    Using Internet Recovery (Option + Cmd + r) installs the OS the computer shipped with.(here, Mavericks)
     
  7. Taz Mangus macrumors 68040

    Taz Mangus

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    Mar 10, 2011
    #7
    Okay, thanks. I was asking if you could keep Yosemite install and still have the recovery partition install Mvericks to the new partition.
     
  8. Bruno09 macrumors 68020

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    #8
    No, because after you update from Mavericks to Yosemite, the Mavericks Recovery partition "Recovery 10.9" is replaced with a Yosemite's "Recovery 10.10" which will re-install Yosemite, not Mavericks.

    Only Internet Recovery will install Mavericks (if Mavericks was the original OS).
     
  9. dj95 thread starter macrumors member

    Joined:
    Oct 25, 2011
    #9
    Thank you for the replies everyone. All up and running now. Chose to create a partition on an external USB 3 disk to avoid messing with the internal SSD, then boot into internet recovery (as previously mentioned the recovery partition is replaced with Yosemite) and install Mavericks onto the external partition. It runs surprisingly smooth considering it's running from an external USB drive! Thanks for the help.
     
  10. KALLT macrumors 601

    Joined:
    Sep 23, 2008
    #10
    Obviously, but that was not the point. Given that Snow Leopard runs without any problems on my system, it is reasonable to presume that you can easily manage two OS X installations on the main drive. Yosemite hasn’t prevented that.
     
  11. Taz Mangus macrumors 68040

    Taz Mangus

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    Mar 10, 2011
    #11
    I thought you were suggesting for the OP poster to try installing Snow Leopard on his 2014 MBP as you brought it up.
     
  12. snsking macrumors 6502

    snsking

    Joined:
    Jun 10, 2013
    #12
    Yes you can dual boot Mavericks and Yosemite.

    Create a second partition on your drive with enough space, download the Yosemite installer from the app store, run it, select to install it to your 2nd partition, and let it run through.

    Once its done you will have one partition with Mavs, the other with Yosemite. You can hold the option key at boot up to select which one you wanna use.

    Be aware that yosemite will upgrade your system firmware regardless if you installing it on the 2nd partition. It will go from b03, to b14.
     
  13. Taz Mangus macrumors 68040

    Taz Mangus

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    Mar 10, 2011
    #13
    The OP already has Yosemite installed.
     
  14. snsking macrumors 6502

    snsking

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    Jun 10, 2013
    #14
    I don't see why it wouldnt work. My only concern would be the system firmware. Would Mavs try to install the system firmware that is used by Mavs? or would it just be fine?

    You can always just restore your laptop, do an internet recovery for macs, and then install yosemite on a 2nd drive
     
  15. thadoggfather Suspended

    thadoggfather

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    Oct 1, 2007
    #15
    The firmware is not downgrade able.

    it will remain on the same one, even with Mavericks installed.
     
  16. Taz Mangus macrumors 68040

    Taz Mangus

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    #16
    What I was referring to was that the OP already has Yosemite installed and you were suggesting to install Yosemite.

    ----------

    I have Snow Leopard installed on an external hard drive. I have Yosemite installed on my 2011 iMac. I have no issue booting to Snow Leopard on the iMac. Is it the case that the firmware has not been updated on my iMac? Or is it the case where the firmware is only updated in certain cases?
     
  17. snsking macrumors 6502

    snsking

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    Jun 10, 2013
    #17
    Yeah I misread that the OP had Mavericks and wanted Yosemite on a 2nd partition. Its the other way around.

    You are able to downgrade the system firmware in some cases but there is little information on how to do it.

    I would assume it would be safe to do, I just dont know how the Mavericks installer would react if the user already has a higher system firmware version.

    Would it just detect it and move on? Or would it detect it as an error?
     
  18. Taz Mangus macrumors 68040

    Taz Mangus

    Joined:
    Mar 10, 2011
    #18
    Another question I have, if the OP installed Mavericks to an external hard drive and then booted to the external hard drive would that work? And if they were able to boot to the external hard drive, could they then install Mavericks to a new partition on the internal hard drive and boot to it?
     

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