How to create yourself a backdoor to downgrade OS X

Mon, Sep 28, 2015

How-to

In a few days Apple will release a new major version of OS X. This year it is OS X El Capitan and as in the last years with Yosemite and Mavericks the upgrade is free of charge and will be distributed via the Mac App Store.

Though most of us are excited to try the new version, not everyone is aware that Apple doesn’t allow a downgrade. So once you have upgraded to El Capitan and not everything is running as you expected it, there’s no out of the box path to go back to your previous installation of OS X.

One way of downgrading of course could be to create a Time Machine backup and in the unlikely event of having to revert to your older OS X you can replace your installation with the backup. However that will take a while and you first need to upgrade.

Or you could google it, see whether others have encountered issues. Well, not really workable, as nobody is alike and hey, we are curious and want to get our hands on it, right?

So what’s best practice to test a new version of OS X to see whether you can use it in production?

If you have several machines, obviously the best way is to try it on a machine that is not critical in our production environment. However that has two downsides:

  • First, you really want to test the new version of OS X on your most use machine to see whether all applications and small tools are running fine.
  • Secondly, not everybody has two machines

Here’s how to safely test a new OS X and being able to revert immediately or – even better – to just temporarily revert to a previous version of OS X.

Important is that you do this BEFORE you install OS X El Capitan.

Best Practice to safely test a single Mac with a new version of OS X

Here’s my way of creating myself a backdoor to be able to revert and downgrade to a previous version of OS X.

If you just have one Internet device, please print this to be able to reference.

Before you start, please turn off Time Machine, as it might mess up your backups when working from a cloned disk.

  1. Buy an external hard disk that is at least as large as your internal hard disk (“Macintosh HD”) and connect it to your Mac.
  2. Use Disk Utility to format the external disk as “Mac OS Extended (Journaled)” and in options “GUID Partition Table”.
  3. Download Carbon Copy Cloner (http://bombich.com/). It has a free trial for 30 days, however I strongly recommend purchasing it (I have no shares in that company ;-) as it can save you a lot of trouble and money.
  4. Clone your hard disk to the external disk. So source is “Macintosh HD” and target is “External Drive”. Clone it completely. Everything. Bootable.
    Note that CCC tells you what it will create before doing it. Read the manual if you are unsure.
  5. Important: Reboot your Mac and hold the Option key pressed. Boot from the external hard disk. Note: This might take  longer than normal, as you are using a connection that is typically a bit slower than an internal hard disk. Test whether everything works as before (ignore the slight difference in speed), it’s important to check that this is a real clone. If everything has worked fine, that’s your 1:1 backup and it’s even bootable.
  6. Shut down your Mac. Unplug external hard disk. Restart.
  7. Now upgrade your Mac to the new OS X (so to OS X El Capitan).
  8. Look for upgrades of the applications and tools you use, update your printer drivers etc.
  9. Important: Test everything thoroughly. Test all the applications you use frequently, all goodies, see whether you like the UI, whether all your input and output devices work (scanners, printers etc.). You can even simulate production.

If everything works fine, you are done and can enjoy the new OS X. How does Murphy says “The only backup you’ll ever need is the one that you didn’t make.”

Ignore the rest of this list ;-)

 

Backdoor 1 (temporarily revert to the previous version of OS X)

If something does not work correctly or you can’t produce a specific file anymore and therefore you want to temporarily switch back to your previous version of OS X – maybe for one job –,  here’s how:

  1. First make sure that you save everything important that you have created since using the new OS X.
    So if you created a QuarkXPress document under El Capitan already and you’ll still need that, save it to a USB stick (or something similar).
  2. Now shutdown your Mac.
  3. Connect the external hard disk again.
  4. Important: Start your Mac from the external hard disk (by holding the Option key and choosing the external drive).
  5. Work.

Please take special care when using this way and remember that you are then working with two boot volumes. So once you decide for one, you need to make sure that all your work is copied from both disks.

 

Backdoor 2 (permanently revert to the previous version of OS X)

If you feel the new OS X isn’t right for you yet and you want to work with your previous version of OS X for the next weeks (and then maybe test again), here’s how how to downgrade OS X permanently:

  1. First make sure that you save everything important that you have created since using the new OS X.
    So if you created a QuarkXPress document under El Capitan already and you’ll still need that, save it to a USB stick (or something similar).
  2. Now shutdown your Mac.
  3. Connect the external hard disk again.
  4. Important: Start your Mac from the external hard disk (by holding the Option key and choosing the external drive).
  5. Use CCC (Carbon Copy Cloner) to duplicate the cloned drive back to your internal hard disk. Clone everything back from source “External Drive” to target “Macintosh HD”. That’s important, don’t clone it the other way around.
  6. Shut down your Mac. Remove external hard disk.
  7. Restart your Mac.
  8. Work

Everything should be now exactly the same as it was before you upgraded OS X. Test it to be sure. Remember to copy any files you saved on the USB stick to your drive and continue working. Make a mental note to try that in a few weeks again once the applications that haven’t worked correctly are updated to support OS X El Capitan.

 

Let me know please if this worked for you.

 

Another way of keeping a backdoor open (provided you have enough RAM and can compromise on speed that is) is to virtualize your previous (or new) OS X. Apple allows virtualization of OS X on OS X. So get Parallels or VMware Fusion and install the new or previous OS X you need. And that’s probably a topic for another blog post…

, ,

This post was written by:

- who has written 78 posts on Planet Quark.

Both an engineer and a layout artist, Matthias bridges the gap between technology and people. - Before joining Quark, Matthias pioneered print, Web, and multimedia products for multiple German publishing companies. Since 1997 he has played a central role in shaping Quark’s desktop and enterprise software. Starting 2003 Matthias has focused on Quark's interactive and digital publishing solutions. He is an active participant in design and publishing communities and represents Quark in the Ghent PDF Workgroup. - Matthias is a frequent speaker at seminars and conferences worldwide, helping both individual designers and large organizations to uncover the possibilities and implications of digital publishing, including the business considerations, design and technology implications, and business capabilities offered by digital design and publishing tools. - Since February 2014 Matthias heads Quark's Desktop Publishing business unit and is therefore responsible for QuarkXPress.

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6 Responses to “How to create yourself a backdoor to downgrade OS X”

  1. Matthias Guenther Says:

    One word of advice, this is best practice even if you are optimistic and think that everything will go well and all your applications claim to support the new operating system.

    It’s risk management. Some people also call it due diligence. It has nothing to do with being pessimistic or overly optimistic. ;-) And it also doesn’t indicate anything about the expected quality of a new version of OS X.

    It’s like wearing seat-belts in a car, paying for insurances or having a back strategy for your computer. Typically nothing happens.

    However if you see a risk – even with a low probability – that is quantifiable, significant and/or has a large impact on your life or finances, you should try to reduce or remove it.

    Here the cost are almost zero:
    A live backup will only costs you a few hours cloning and you need to have a backup disk available.
    And the good news are, in case something does go wrong, even if you don’t expect it, the impact is then zero. And otherwise potentially huge.

  2. Matthias Guenther Says:

    Falls jemand das ganze auf Deutsch lesen möchte, Detlev Hagemann hat es auf seiner Webseite übersetzt: http://www.xpress-upgrade.com/8-startseite/startseite/481-upgrade-auf-neue-os-x

  3. Matthias Guenther Says:

    Thank you, Wolfgang, for pointing this out:

    In case that your Mac is your only Internet device, make sure to print these steps (on paper!) before starting!

    I’ll add it to the post.

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