Creating a bootable external drive in OSX and why you should think about doing it.

usbleopardCatchy title huh? This is a short post but one that I hope might help a few people out. Firstly, if you are a PC user then i’m afraid I can’t help you with all the details, but at least read the first few paragraphs to find out why you might want to do this. In the past 18 months I have had three hard drive failures, 2 in laptops and one in an external USB drive on my desk. It happens and I hope by now we all know that. I’m not going to preach on backing up your files, that’s for another time…..

A few times in the last few months I have found myself working in a location that is fairly remote. No Apple store or computer parts store within a thousand miles, and not somewhere that gets any kind of speedy mail-order servicing either. So what would happen if one of my laptop hard drives had failed in one of those locations? This is mostly relevant to photographers who travel a lot, and especially those who visit remote locations, but the solution is actually fairly simple and remarkably cheap. A bootable external drive that can run Mac OSX is the answer. It doesn’t even need to be a 2.5″ hard drive, you can actually boot to Snow Leopard directly off a USB keyring as long as its big enough!

A full install of Apple Snow Leopard needs just a little bit more than 8GB of space so if you have a thumb drive or an old 2.5″ hard drive lying around that is bigger than that then you are good to go. I did this recently with an old 320GB 2.5″ drive that I had in a draw. If you have an old hard drive you will need to buy a SATA case for it but the cheap and cheerful ones can be had for about $30 from any good computer store. Now if you want to try this on a USB memory stick you aren’t going to have much room for things other than the operating system, but at least it would get you back up and running and able to download your memory cards to something. If you are using an old hard drive (or a new one as they are so cheap these days) then you will be able to install OSX and all your necessary programs on there too.

The first step is to plug the USB device into you computer and open up Disk Utility from the utilities folder in the applications section. On the left hand side find the drive that you wish to install OSX onto and click it. Now click on the button labeled partitions which will open the partition configuration menu. From the drop down box select “1 Partition”.

Screen shot 2010-04-28 at 11.17.32 PMNow click the options… button at the bottom and make sure that you select GUID Partition table. This is the really important part! This is what allows your computer to recognize the disk as a bootable disk on start up. Click OK and then click Apply on the partition screen. WARNING!!  This WILL erase everything on the disk! So check the disk before you do it!

Screen shot 2010-04-28 at 11.17.42 PM

Now go ahead and insert your Snow Leopard install disk into your DVD drive. Click on the option to install, and when prompted, select your newly formatted USB drive as the install destination. The progress screen will come up and its going to tell you it’ll need some time to install. Bear in mind that all the data is being transferred through USB now so it’s going to take longer than it normally would. Part way through the install process your computer will automatically re-boot and boot from the USB device. Once it’s done you will see the Snow Leopard intro on the screen and you are done! Now install all the essential programs you need to get your work done like photoshop or lightroom and shut down the computer.

Now here’s the next important thing to remember. With the USB drive plugged in, when you turn your computer on you need to hold down the OPTION key if you want to boot from the external drive as soon as you see the white screen appear. If you do this and keep holding it, eventually a screen will appear that will ask you which drive you want to boot from. Selecting your USB drive will allow you to run OSX from that just as you normally would. Things might seem a little bit slower running from USB, especially if its on a thumb drive, but I tried it recently and was actually rather surprised at how well it handled things.

So if you have a drive lying around at home, why not do this one day and keep the USB drive hidden in your travel bag. You never know when it might come in handy! The second scenario is that your computer stops working entirely while you are away. Well now you just need to find another Mac somewhere and you can plug in your USB drive and boot from that to have access to all the programs you need !

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Dan Carr

Founder of Shutter Muse, full time photographer and creative educator. Dan lives in the Canadian Yukon, but his wanderlust often sends him in search of images all around the world to meet the needs of clients and readers alike.

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