I have a MacBook Pro 17" Late 2011. Today I removed to optical drive and installed a SSD (where the HDD was) and moved the HDD to the optical drive location.

Now I want to make the SSD my primary drive, and use the HDD for storage only. the problem is that I can't clone all the HDD to the SSD because the former has 750GB and the latter is 250.

I only want to install the OS to the SSD. I don't mind installing all other apps manually afterward, but I'm just not sure what should I do next.

How do I install only OS X on the SSD and make it the main boot disk?

  • Pretty sure the install will ask you what disk you want to install the image, after that is done, you can go into preferences and select the startup disk to be the SSD drive
    – tik27
    Aug 10, 2015 at 20:21

4 Answers 4

  1. Download the installer to the current system
  2. While it downloads, partition the SSD as GPT/OS X Extended
  3. Run the installer and install the OS onto the SSD instead of the current boot drive
  4. Use Startup Disk preference pane to set the new SSD as the boot volume default - NVRAM points to the SSD for all subsequent boots

If you boot to the Recovery Drive (restart holding Command and R) you'll get a window with an option to "Re-install MAC OSX". Choose this and then choose your SSD as the target. When installation is complete, go to System Preferences > Hard Disk and select your SSD as the boot drive. Alternatively, you can reboot holding Alt/Option and you will be asked to choose which disk to boot from.

When you are 100% certain the SSD is working then you obviously have the option of deleting all system files from the original HDD; or keep the system intact and you will have a 100% functioning back-up to boot from in the event the SSD fails. If you need to maximize storage go ahead and delete all the system files on the HDD. At that point it should be recognized as a just a storage device, not a start-up drive. Better yet, you might consider erasing the HDD completely and then re-populating it with your data files. Of course, to be safe you'll want to create a complete back-up of the HDD before you start any of this.

P.S. I also have a 2011 17". Love it. Was thinking about doing something similar to extend its lifetime. Problem is these computers have had problems with their GPUs dying which scared me away. Please let me know how it goes and how much faster the computer is with the SSD. That might encourage me to do this.

  • i still own a mbp 2011 13in. installed OS on SSD and used internal builtin-HDD as secondary drive.. it's super fast now.. Opens programs very quick. And ssd is really a good upgrade.
    – MFarooqi
    Jul 18, 2018 at 14:03

I'd use Carbon Copy Cloner. You can select what to copy over & leave the other data behind on the old drive.

Change the old drive name to something else, then the new one to what the old was called.
Select the new drive as default boot in System Prefs > Startup Disk & reboot.
The new drive will be bootable & indistinguishable from the old, except for your excluded data content.
Clean up the old OS from it once you're satisfied you got everything you need.

Saves all the effort of a clean install + migrate (where you'd have to select what to copy over anyway.)

This is essentially what I do before every major OS update, or so I can test out OS betas without losing the option to revert cleanly.
[I always swap to a new Time Machine drive when I do this, so I'm not sure what steps you'd need to take in order for a single TM backup to continue uninterrupted]


Let's give you another option: Fusion drive

1) backup the 750GB to a time machine/capsule (You are making backups, aren't you??)

2) using the Installation USB you've created, you boot from that, and follow the instructions on the net to create a "custom"/DIY Fusion Drive. (basically open a terminal window, and fuse the two drives using diskutil)

3) then exit the terminal window, and use the option to restore from the TimeMachine/capsule.

Do be aware that that recovering will take a while (In my case with my files, several apps with loads of small files, ±12hours over SATA for ±680GB)

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