I've got a late 2008 13" Macbook (Unibody)(A1278) with OS X El Capitan and I want to add a new SDD or HDD as I'm running out of space.

I know the hardware procedure but I'm very confused about the software side of it.

How would I get Mac OSX onto the new SSD or HDD? Would I need to use an installation disc when I add the new SSD or HDD or can I put Mac OSX onto the new hard drive by transferring it over from the old on?

  • Could you not do a Time Machine (you should do this anyway) -> insert the new SSD -> boot to recovery and do a net install of the original OS X that came with your machine and then do an upgrade to El Capitan through App Store once the device has been restored? – Kinnectus Aug 10 '17 at 11:55
  • I was led to believe that when you insert a new drive into your mac and powered on, the device prompts you with the message, "no OS has been detected, would you like to download and install the latest MAC OS" just click yes and follow the onscreen instructions to install Mac OS – TiO Aug 10 '17 at 13:26

What I would suggest is:

  1. Go to the Mac App Store and download the latest MacOS version you have available to you.
  2. Once the download completes, grab http://diskmakerx.com/ and install it on your Mac. This lets you copy the installation image to a USB drive.
  3. Once this process is complete, turn the laptop off and switch out your drives.

  4. Be sure to also have something like this on hand to plug your current HDD in to.

  5. Now, reboot with the MacOS install drive plugged in and hold the Option key.
  6. Select the install drive to boot off of and wait the 30-45 minutes I usually find myself waiting for MacOS to install.
  7. Once the process is complete you will have a few setup prompts to go through. One of these regards importing data from an old Mac.
  8. Plug in the old drive and use this automatic tool to get all your data back.
  • Your second link is broken. – Ramhound Aug 4 '17 at 19:58
  • Similar to the answer by bSmart - this assumes an 08 Mac will easily boot from a USB key. There is a high probability that it will not. – Tetsujin Aug 5 '17 at 10:26

Once the hard drive is installed, you would need to boot the computer to an installer. An installation CD would do the trick, if you already have one (your particular computer would have come with a CD; newer models don't, since macOS is no longer installed using physical media). If you don't have the CD anymore, you can follow this article to create a bootable installer on a flash drive: https://support.apple.com/en-us/HT201372. That does have to be done before you install the new hard drive, obviously, or else done from another Mac.

Once you have your installer, you can boot to it by holding down the Option key as the computer powers on. When you have it loaded, use Disk Utility (it'll be on the screen along with a few other utilities) to format the new internal drive and name it whatever you want (the default is Macintosh HD).

After that, it's just a matter of moving over your content, which I'd recommend using Time Machine for. Good luck!

  • 2
    @bSmart Signatures (in general) especially those that link to our personal website in your answers are not allowed. Future answers with that signature will be flagged for moderator intervention – Ramhound Aug 4 '17 at 19:54
  • an 08 quite possibly won't be able to boot from USB. 09 is about the transition point, & even then some machines with a Superdrive still cannot be persuaded. – Tetsujin Aug 5 '17 at 10:08

Not a free method, but a reliable one - with a belt & braces structure & no need to try persuade an old Mac to boot from USB [which can be tricky]...

  • Get an external USB drive adapter/enclosure that will take each of your drives, new & old.

  • Get Carbon Copy Cloner which can easily make a bootable clone from your existing system whilst it is running.[1]

  • Test the clone will boot from the external drive enclosure by holding Opt ⌥ at the startup chimes.

  • Once confirmed, swap the drives over.

  • Test again that it will boot from the new internal drive with the old one completely disconnected. You may need to hold Opt ⌥ again the first time, then once booted, set it as the default startup drive from System Prefs.

If no joy, rinse & repeat with the old drive booted externally, as your old drive is completely untouched. [I've never known this method to fail, but it's always sensible to have a safety net]

You have now moved your entire working structure in a single safe step to a faster/larger drive, without having to reinstall anything.

[1] Pro Tips:
Rename your old drive immediately before starting the clone process. e.g. to 'Macintosh HD old'.
Format your new drive [whilst mounted externally] as GUID/HFS+ in Disk Utility & call it the correct name, e.g. 'Macintosh HD'
Set up & start the clone process.
When you then reboot to your new drive, the system will be fooled into thinking nothing changed.
Don't do any 'work' whilst it's cloning. Disconnect your net connection. This step is not vital but it can save for instance an email being received in the middle of the process which then fails to be synced to the clone.

  • Thank you so so much!!!! Very nice informative steps. I'll definitely be using this safer option. Thanks again. – BR26799 Aug 6 '17 at 19:40

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