1. Welcome to the new MacRumors forums. See our announcement and read our FAQ

downgrading Mountain Lion to Lion

Discussion in 'OS X Mountain Lion (10.8)' started by nrajack, Sep 26, 2012.

  1. macrumors member

    I'm about to pull the trigger in a new Mac but have a question: is it possible to downgrade ML to Lion? I remember when Lion came out that if a Mac already had Lion you couldn't backdate to Snow Leopard but if you upgraded SL to Lion you could backdate to SL. As we all know all new Macs are coming with ML and not all of my apps are updated to work in ML.

    Previous Macs around here have Tiger and SL. So I don't have a copy of Lion around which raises another question: is Lion somehow available from the App store or do I have to go third party to get a copy of Lion (assuming I can downgrade ML to Lion)?

    I've seen several things on the web about backdating ML to Lion but those were only if the machine in question had been upgraded to ML from either Lion or SL.
  2. macrumors 68020


    If your generation of Macs originally shipped with Lion, you can "downgrade" to Lion. I don't think it's in the Mac App Store but maybe you could find a Lion USB flashdrive on eBay or Craig's List.

    Here's the problem though: you can't really "downgrade" easily. You would first have to back-up all your personal files onto an external hard drive. Then, you would erase your Mac's hard drive. Then install Lion. Then move back all your personal files from the external to the Mac and finally reinstall all your applications.

    It's a bit of a process but I've done it. And if it's really worth it to you, you should do it.
  3. macrumors 604

    All currently available Macs came out before ML so they will be able to run Lion in terms of drivers etc. I've upgraded and downgraded my rMBP back and forth in the days just before ML was publicly released and afterwards when I was writing my book.

    I noticed that even though the ML upgrade would change the recovery HD partition to 10.8, so you could not use it to reinstall Lion, you could still reinstall Lion by using the internet recovery.

    However, I am not sure if the recent firmware updates have changed that and I'll only be able to check later tonight. You could still get lucky and receive a Mac without the latest firmware and may be able to reinstall Lion using the internet recovery.


    I don't think that will be a problem for the OP, since he will be buying a new Mac and I assume this would be the first thing he would be doing before putting any data on it.
  4. macrumors member

    Last things first - you are exactly right. I would do the downgrade to Lion before putting anything else on the machine. Not interested in upgrading my old machines.

    First things next - I understand all currently available Macs came out before ML but wasn't that the case, to a certain extent, when Lion came out after SL? The way I understand it Macs that came from Apple with Lion couldn't be downgraded to SL because of firmware changes. I think that's what you're talking about in your last paragraph, right? That's something that doesn't seem to be talked about on the net that I can find (at least with some modicum of ease on Google). Thanks for any info you can shed one way or the other.
  5. macrumors 604

    I recall that people with early 2011 MBPs were able to downgrade back to SL, even if they purchased their MBPs after Lion came out, but I've not seen any posts about doing this on a late 2011 MBP, so I am theorising that the situation is the same.

    I've not seen firmware updates after ML came out until the 10.8.2 update. I still need to check if this firmware update has updated the internet recovery. I am assuming that this update may block the ability to install Lion, but I'll give it a go and see what happens. I don't think Apple would have put some special firmware updates on Macs that shipped with ML to prevent Lion being installed, but you never know these days. Being able to dual boot Lion and ML on the latest Macs is a perfectly justifiable use case for developers so preventing that would be a crap thing to do.
  6. macrumors 604

    Apologies for consecutive posts, but this is an update.

    So I cloned my rMBP's drive and then deleted it and ran internet recovery. Even though I was running 10.8.2 with the latest firmware, I can still install Lion via internet recovery. I can't verify whether this holds true for other Macs built after ML was released, but I have a suspicion that it will be the same.

    Whilst cloning I noticed another option that may work. Carbon Copy Cloner will allow you to create to a Lion recovery HD on an external drive, even from ML. In theory that means you could create a Lion recovery HD, boot of it, erase the internal storage (probably best to clone it first) and then attempt to install Lion.

    Since you have 14 days to return the Mac for a full refund, you could give either of these options a try without risk.
  7. macrumors regular

    theSeb - this is very helpful info...thanks for posting.

    It would certainly be interesting to know, should the OP decide, if a mac that ships with ML could be downgraded easily. AS FSMBP stated a USB disk with Lion could be quite useful, otherwise how would the new machine even know Lion exists in recovery? But like you said 14 days should provide time to sort it out...
  8. macrumors demi-god


    This is my understanding... If your MacBook is a 2012 before Mountain Lion came out. it has a special build of Lion (10.7.4) for those models. You couldn't just download plain 10.7.4 and install it, it had to be that special build because of drivers. The only way to reinstall Lion was though Internet Recovery or a cloned drive with the special build.

    Units shipped after Mountain Lion came out. The Internet Recovery installs Mountain Lion now (before ML). So if you have a clone drive contains special build of Lion, you would be able to transform that clone on to the MacBook.

    This is where it gets grey area for me:

    Lion is now 10.7.5 if you have access to the full installer from the MAS, this in theory install 10.7.5 on any mid 2012 machine. Why would this work is because it's the full install, it should have all the new stuff for the new models already in it. Only one problem Lion is no longer on MAS, those that bought before it was pulled can still download it. Or call Apple to see if they can give you a download key.

    Because of drivers issues that's why you can't use any 10.7.4 install. The only thing to do clone 10.7.5 or get your hands on 10.7.5 install.

    The MacBooks 2011 that came out with Lion was really designed for them (Lion)

    I hope that gives some help in that mess. LOL

  9. macrumors 604


    Also interested in finding out.

    Apple care offered me a new laptop but i don't want ML. A family member, however, got the same model apple is offering me before they started shipping with ML so then I could just trade.
  10. macrumors demi-god


    Yes that's one way. However with out making a bootable install, it would have to be 10.7.5 install. If you want to totally erase the hard drive and have bandwidth, you can do the Internet Recovery (Note: I don't know which it's going to download now. 10.7.4 special build or 10.7.5.

    Note: Internet Recovery downloads the installer and then installs the OS, so it takes some time. Mine took 2 hours (I'm on 5Mbits connection).

  11. macrumors 604


    Thanks for the info.
    We upgraded the computer to ML as a free up to date program, but I'm assuming that I can downgrade back to L. I wonder if Internet recovery will only download ML though, now that I have it. Forgot to check that.

    Edit: I have L on the download history of MAS of my account :)
    edit again: looks like internet recovery gives you the option to download Lion, even if you have ML running (provided your computer originally shipped with Lion)
  12. macrumors demi-god


    Yeah, that's what I am talking about. If it come with ML then your screwed no easy way to install 10.7.5 to a mid 2012 MacBook (All of them).

  13. macrumors member

    Thanks all for your advice. The machine specifically I'm looking at is the 21.5" iMac with the 2.8GHz I7 chip. Has enough expandability for what I want to do - music recording & production. The Thunderbolt port will allow me to use an expansion chassis for the ProTools HDX cards or HD Native card as well as hard drive expansion. I don't know if this would run into the same problems mentioned here as the MacBooks and 10.7.4 (plain vanilla versus special version).
  14. macrumors 604

    Are you 100% certain of this? Simply holding cmd+R will boot you into the recovery partition (Recovery 10-8), if one is present and will only allow you to reinstall ML. You need to actually format your entire startup disk (not just the Macintosh HD partition) and then hold cmd+R to go into Internet Recovery, which takes ages to start up. This is why I had to format my entire start up disk last night.

    I would like to confirm that 2012 Macs released after Mountain Lion can only install ML from Internet Recovery.
  15. macrumors demi-god


    A true Internet Recovery will install whatever OS the machine shipped with as it is tied to the serial number. So yes, if the machine shipped with ML on it, a Internet Recovery will detect that serial number is tied to ML and install ML.

    If it is a factory Lion machine, even with ML installed, a true Internet Recovery will detect the serial number is tied to Lion and give you Lion.

    Not to be confused with a Recovery HD reinstall which will reinstall to whatever version Recovery HD you have.

    Long, boring article on this here.

    Apple has not done a very good job explaining this IMO.
  16. macrumors 604

    Thanks for the info. There are some things that Apple really needs to include more technical info for, because sometimes things don't just work.
  17. macrumors member

    So this means if I can get my hands on a copy of Lion I can install it on a machine that comes with ML already on it? Is it even possible to get a legit copy of Lion to do this? And from where - I doubt from Apple.
  18. macrumors demi-god


    I am going to say "maybe"... I know when the new Macbook Airs came out they had a special build of 10.7.4 on them. So if you could get your hands on a full install of 10.7.5, theoretically, that would work... but I honestly don't know.

Share This Page