My dad would like to encourage me to learn how to program in C++, but he doesn't want anything that could possibly go wrong with any of the computers that we own while I am doing so to affect any of the data associated with their other user accounts. As such, he would like to give me an external drive for me to use as an isolated programming environment. This would be relatively straightforward to set up, but I was wondering if I could install OS X on this drive in such a way that I could boot it no matter which one of my family's computers it was hooked up to so that I could use whichever one is available as they become so. Is it possible to do this at least for a late 2007 aluminum iMac and a 15-inch MacBook Pro that my dad bought late in the summer of 2011?

  • 3
    Why not use a VM?
    – napcae
    Feb 17, 2014 at 15:26
  • 1
    Or just use a user account without Admin rights, will be quite difficult to break anything for other users that way.
    – nohillside
    Feb 17, 2014 at 15:47
  • If you want to edit the major version of OS you plan to use, we might be able to offer more helpful answers.
    – bmike
    Feb 17, 2014 at 16:08
  • @mapcae: My dad's only got one copy of Parallels Desktop 8 for Mac, but I want to be able to learn to program on either of two computers. Besides, wouldn't it be kind of a hassle to move a virtual machine between the two machines? A flash drive might help, but I don't know if I have one that's spacious enough. Feb 18, 2014 at 15:24
  • @patrix: My dad's too paranoid to allow me to have an account to use for programming on our main installation because of how he's never done anything more extreme than use AppleScript or HyperCard before and is quite paranoid, especially when it comes to Terminal (I may need to set some environment variables for devKitPro and PAlib when I finish learning C++ and start programming my DS using my flash cart.) Feb 18, 2014 at 15:31

4 Answers 4


Yes it is quite easy.

For example, my MAC had a bottle of Champagne poured on it (long story, short) and I removed the hard drive and placed it in another machine. I also later took that drive and placed in an external enclosure and booted from it by using the "OPTION" key when booting. This brings up a list of all accessible drives INCLUDING NETWORKED DRIVES if accessible. So you could configure your DEVELOPMENT drive on your network and boot from it HOWEVER unless you have GIGABIT network it would be slow.

So to create an external bootable self contained OSX drive I recommend the following tutorial, BE ADVISED it will clear off any data on the external drive and your doing all of this at your own risk.


  • 1
    There is still the question of how many different Macs such a drive will work with. As it says in ht5911: "This procedure installs a version of OS X that is compatible with the Mac it was created with. Using this OS X system with a different Mac model may produce unpredictable results." Feb 17, 2014 at 15:50
  • That's what I was afraid of! Feb 18, 2014 at 18:45
  • It will like function in all macs that support that particular OSX version. Mac OSX is a fairly portable OS. I've booted a single version off a dive on an iMac, Macbook and Macbook pro without issues. OSX has many more drivers automatically installed by default then a single machine would use.
    – VJ Kevlar
    Feb 19, 2014 at 2:14
  • @VJKevlar: That's great! Feb 19, 2014 at 15:32

In general, no. Apple maintains a list of minimum builds that guarantee for a specific hardware model, the drivers have been included to make everything work.

Your inevitable choice of build version to install on the USB drive will mean that some computers will be too old (don't meet minimum requirements for your build) and some too new (your OS is too old for them).

In limited cases (and even in wide ranges of computers spanning 4 years) one build can work for a whole host of computers. Also, the OS can work well enough in many cases if you are missing a WiFi driver or something minor and can run updates to get the required additions when you take an older OS onto "unsupported" newer hardware.

You can have much success with an external drive and multiple computers - especially once you check the build details and requirements for the OS and computers you intend to use. I say go for it, even though there isn't a universal, all encompassing image for all hardware shipped.

So, setting aside the new Mac Pro - I would expect every Mac manufactured in the last 5 years to run any 10.9.1 installed from a current 2012/2013 install. From a practical standpoint, I would run the install from the newest Mac you have which is the 2011 model to get the most recent version of things and to download the installer from the App Store and not reuse an old saved one in case Apple has rolled new drivers into the current installer.

  • I think that my Dad already burned a Mavericks install DVD (I'm pretty sure that we used the instructions at macworld.com/article/2056561/…, except that we used Spotlight's 'File Visibility is Visible or Invisible' query to find OS X Base System.dmg and then used Disk Utility's 'Burn' command set to create the DVD (yes, it fit on a single-layer DVD.) Anyway, I'm pretty sure that I can install OS X 10.9.1 using a 10.9.0 disk if I'm connected to the Internet (I'll plug an Ethernet cable into the MBP) so that it can download updates. Feb 18, 2014 at 16:05
  • One last thing: I thought I read your post correctly, but could you double-check my understanding for me? I think that you said to run the installation normally on the 2011 MacBook Pro and then shut down and boot the iMac with my target drive to run Software Update via the Mac App Store. Is that right? Feb 18, 2014 at 18:52

It did not work for me. What I found is that when you install OS X or download OS X from the AppStore, you do not get the same binaries for all Macs. For example, if you get OS X for a 2007 Mac, it will not work on a 2008 Mac. I have a Late-2011 Macbook Pro (not Retina) and installer for it does not run on a Early-2012 Macbook Pro (non-Retina). Different hardware needs different drivers and when installing, the Installer puts a right combination for your current Mac.

It is possible that you will have compatible hardware but it will be much safer (and faster!) to use a NAS for your work and boot Macs normally.


Yes that is possible. I have a 2012 iMac and a 2012 MBP and have an external thunderbolt drive that has Mountain Lion on it installed from the iMac. It boots up flawlessly on both the MBP and the iMac. I use it mainly for those apps that are not supported by Mavericks yet and as an emergency backup for when I'm travelling.


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