[NewsPoster]

We'll say this for when OS X used to come on shiny discs: it was easier to install the thing on several machines, or to start over again if you decided to scorch-Earth your Mac. Now that we install these huge updates with just a click or two, we also lose the ability to easily do it again, because OS X deletes its own installer once it's done. That is in nearly every possible way sensible and handy, but just occasionally, it isn't. Here's how to get the OS X installer, and what's more, keep it on a USB stick for multiple uses.

This a Pointers special, addressing a pair of problems, and this first of two parts was tested on OS X El Capitan. The same process works with OS X Yosemite, and about the only thing that might give you pause is that it needs you to use Terminal. So far, in around 200 Pointers tutorials we've avoided the need for Terminal, but we've no choice this time -- and honestly, we're not now sure why we held off. Terminal is the program that lets you into the guts of OS X to type in Unix instructions directly, and while, sure, you could type commands that destroy your Mac completely, that's a bit of a worst-case scenario.

Gather your gear

You're going to need a Mac, and a USB stick with 8GB of space or more. That USB stick needs to be formatted as Mac OS Extended (Journaled): pop the stick in, run Disk Utility, and choose the USB device. Do be sure to select the right one; there's a strong chance it's called "NO NAME," but you can't be sure. If it's on the list after you've inserted the USB stick and it isn't when you eject that, you've got the right one.

Copy off anything that's on it that you care about, and then let Disk Utility format it the way you say from a drop down list. At 8GB, it's not going to take long. Do this for us, though: name the drive Hello. It's important. The name "Hello" isn't important, but that you name it a specific way is.

With that done, you need the OS X Installer, which you can only get from Apple. You already got it when you said yes to upgrading to El Capitan, but then Apple tidied it away again. As big as the OS is, it's still an app you've downloaded from the Mac App Store, though, so it's still one that's listed in your Purchases tab. Open the Mac App Store, click on Purchases, and then scroll. For some reason, we found that trying to search for "OS X" or even "El Capitan" just didn't seem to work, so we had to scroll and scroll and scroll. On the way, though, we did find OS X Yosemite, too, and at some point we'll make a separate bootable installer version of that as well.

Download OS X, and your Mac will say that you've already got it, are you sure? Say yes. Let it download, but then as it completes and it again asks if you're serious that you want to use it, this time you say no. You don't want to run this OS X installer, you want to keep it. It'll be in your downloads folder: drag it into Applications.

Terminal

Open Terminal from the Applications folder, or just use Spotlight. Maybe because we use Terminal quite a bit, just typing "ter" in Spotlight is enough to bring that up for us. When it's running, and you've got that completely friendly black screen with the pulsing cursor, copy the following and paste it in to Terminal:

sudo /Applications/Install OS X El Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/Hello --applicationpath /Applications/Install OS X El Capitan.app

CreateInstallMedia is an Apple tool for doing exactly what we want to do: it'd be nice if this were included in the more visible, more visual OS X utilities, but it's the official app for doing this. You'll be asked to enter your password: it's your Mac's main password. Sometimes, and we're not clear why this varies, but you can be asked to confirm that you want to erase the USB stick: you do.

You're done

People who claim you can get more done by typing commands into Terminal than by pointing and clicking on icons have a point. We're still not listening to them, but they have a point, and this may be proof: having typed or pasted that command, your password and perhaps Y for Yes about erasing the USB stick, you don't have to do anything else. Terminal and the CreateInstallMedia command does the lot.

It can take some time. You'll see a kind of text progress bar: it will display a sort of text completion bar with "10%... 20%..." and so on until eventually, possibly as much as half an hour, it says Done.

Now type the word "exit" into terminal, and quit the app. You can eject the USB stick safely in the usual ways, and now take it to any Mac that you own, that you want to install OS X onto. However, as a caveat, be sure to test that the stick does actually boot before you need it! We've made many USB boot sticks over the years, and some media just can't be used as a boot drive -- we haven't figured out a reliable way how to tell in advance, but better to be certain that it'll work in a pinch before the pinch arrives.

There are many types of pinch

What you've just done will see you right the next time you have to update any of your Macs to OS X El Capitan, and you'll like the convenience of it. You'll bless the convenience if your Mac has gone so wrong that you have to install a new drive, or just plain nuke the old one to start over. Yet that's not the only advantage to having OS X on a Stick.

If it's a relief to have one OS X on your USB stick, it's got to be twice or three times as great to have two or three versions of it there. If you're having to maintain many Macs, and you know some of them will never be upgraded to OS X El Capitan, this is your fast route to sanity. We're just going to keep you waiting for that until Friday.

-- William Gallagher (@WGallagher)

[bobolicious]

...this is one of my favourite things in the post Snow realm - universal install from a fast(er) silent disk... Long gone are the pain of enablers, machine specific CD or DVD, and archive reinstalls are so fast & easy, especially on an SSD disk...

Highly recommended, especially with the cost of USB sticks these days...

And DFA now seems to allow many disk partitions, for alternate clean, test & legacy OS installs...

[Mike Wuerthele]

Hold that last thought, Bob.

[foo2]

Even easier: download http://diskmakerx.com/ and use it.

[panjandrum]

I too have used diskmakerx for this function with excellent success. Seems to work well and is easy to use.

[Mike Wuerthele]

There is a method to our madness - stay tuned!

(that, and DiskMakerX needs to be updated with every OS revision, the terminal commands do not, so, they're good to know)

[iSkippy]

Two quick notes:

In the third paragraph, under "You're done," two sentences seem to be duplicated.

Also, I'm not sure if the createinstallmedia command-line tool does this for you or not, but it's a good idea to make sure your drive is formatted with the GUID Partition Map (also known as GPT) before proceeding, as Intel Macs can only boot from drives formatted with GPT. To do this, click on the drive itself, rather than the partition (usually identified by the make or model of drive, like Lexar, Kingston, SanDisk, etc.), then click Erase; you'll have the option of choosing the Partition Map there.

[Mike Wuerthele]

Originally Posted by iSkippy 

Also, I'm not sure if the createinstallmedia command-line tool does this for you or not, but it's a good idea to make sure your drive is formatted with the GUID Partition Map (also known as GPT) before proceeding, as Intel Macs can only boot from drives formatted with GPT. To do this, click on the drive itself, rather than the partition (usually identified by the make or model of drive, like Lexar, Kingston, SanDisk, etc.), then click Erase; you'll have the option of choosing the Partition Map there.

I am 95% certain that it does (and DU defaults to GPT/GUID), but point taken, and I'll check on the former.

[no1bass]

Can you also install software such as Drive Genius on the stick?

[panjandrum]

@no1bass; What you want in that case is a bootable, installed copy, of the OS, NOT an OS installer. Not hard to do. Basically just buy a good fast USB 3.0 thumb drive (at today's prices might as well go with at least 64gb), format it for the MAC (GUID + Mac OS Extended (Journaled)) and install whatever OS and applications you wish. Then boot from that when you need to. I won't go into details, but now that you know the steps you can easily google the rest. It's all pretty straight-forward.

[Mike Wuerthele]

... and will be explained in Friday's part 2.