I'm trying to upgrade from my MacBook Pro's original HDD to a SSD. Right now my external HDD, which I installed OSX Mountain Lion on, has to be plugged in to boot. If I unplug it, I get a white screen with a flashing folder icon upon boot up.

I open disk utility and it shows my samsung SSD, which I just repartitioned to use Mac OS Extended (journaled)

EDIT I click finder and it shows under devices: "OSX" which is the name I gave my external HDD currently running OSX.. and "Samsung SSD." OSX has the standard folders on a mac.. Samsung SSD is blank.

How can I get OSX to boot from my SSD rather than the external HDD? Thanks!

Would doing this get it to do that?


  • Do you just want to have the operating system on the SSD or are you looking to put all of your files from the external HDD onto it?
    – tubedogg
    Commented Aug 26, 2013 at 17:22
  • @tubedogg Right now the external HDD I'm talking about was cleaned to put OSX on it. I want to essentially take OSX off of it and put it on the SSD. I have another external HDD with the files and stuff that I'll put on later.
    – Justin
    Commented Aug 26, 2013 at 17:25
  • It's not clear if you have a recovery HD on either drive. If my answer is too confusing, you may need to edit in the results of diskutil list when run from the terminal with both drives connected for us to guide you more explicitly.
    – bmike
    Commented Aug 26, 2013 at 17:32
  • This has been answered previously [here.][1] [1]: apple.stackexchange.com/questions/94615/…
    – 8None1
    Commented Aug 26, 2013 at 17:59

2 Answers 2


It looks like Disk Utility is being extra cautious and not allowing you to unmount the boot drive to copy it. Assuming your copy of Disk Utility is running from the OSX external drive, you will have to power down and try booting into Recovery.

Normally, you press Command R to enter recovery but I haven't tested with no recovery partition on the internal drive, so you might instead boot holding option to see if the OS can find a recovery HD on the external drive.

If you partitioned both drives and have no viable recovery, you will have to use internet recovery or otherwise get a bootable OS that isn't the one you are attempting to copy.

Worst case, return the bootable drive to the inside of the Mac and run an OS installer to re-install the OS onto the SSD. That will make a proper Recovery HD partition that will allow you to boot and run Disk Utility without needing a bootable OS separate than the two drives you want to copy.

  • 1
    I might be missing something but why wouldn't you just use something like Carbon Copy Cloner to clone the external drive onto the SSD? Disk utility isn't being extra cautious, it just can't copy the boot drive in use (hence the reason CCC exists).
    – tubedogg
    Commented Aug 26, 2013 at 18:20

As suggested by tubedogg, use a program, such as SuperDuper! or Carbon Copy Cloner (CCC) to clone your data from the HDD to the SDD. This should result in a bootable copy. However, be aware that SuperDuper! does not copy the hidden OS X recovery partition (not sure about CCC). If you also want that, you should carry out the procedure, explained by bmike, first.

Also go to "System preferences > Startup Disk" and make sure your Startup Volume is selected there.

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