I have been facing an issue regarding a OS X Lion installation in my Macbook Pro 13. I used to have OS X Lion, then I decided to update my O.S to the OS X Mavericks; the update was pretty good, it was successful.

The problem was when I tried to "format" my Mac, during the re-installation of the O.S, a message appeared in my screen saying that the "Recovery partition could not be created", that was weird for me, I am not very good with my Mac yet, so I tried using a OS X Lion installer (which is in a CD), I tried to install from the CD (what many people call a "clean installation") but I got the same result regarding the "partition recovery".

I saw that some of the people mention that it is needed to delete all the partitions created, but in my case, every time I try to delete any of the partitions, it says "cannot unmount disk", and I am not able to perform any deletion over the partitions as mentioned in many tutorials.

So far, I noticed that a yellow alert appears in one of the partitions before pick a drive for the installation:

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Additionally, this is what I have when I open disk utility:

enter image description here

I tried deleting the partitions using the disk utility and even using the Terminal commands (with sudo) but I always get the same error: The disk cannot be unmounted. Please if somebody could help me, I will really appreciate, I've been without my Mac for more than 3 weeks. Thanks in advance.

  • I think you can't format a drive created with a newer version of OS X : You can't format a 10.9 drive with a 10.7 DVD – Thomas Ayoub Jun 18 '14 at 6:50
  • thanks, but even if that's the case I am not able to perform any action on my MAC, I have the option to reinstall the OS X Mavericks when I start the computer but it says that the recovery partition cannot be created. – Marcelo Tataje Jun 18 '14 at 12:19

When you're booted from the CD and looking at Disk Utility, you need to use the Erase tab, not the Partition tab. The EFI and Recovery partitions are hidden from view, so even if you delete all the partitions on the disk, it still won't delete that one.

If that still doesn't work, then you can open up a terminal window, and issue the following command:

diskutil zeroDisk /dev/disk0

That will zero out your entire hard drive, including all your partition tables. But it could take 2-3 hours depending how fast your hard drive is. Once it's done, you can create a new partition and install the OS.

If course, if you're really pedantic like me, you'd remove all media from the optical drive and USB ports, zero the hard drive, power off, zap the PRAM, reset the SMC, and then boot from Internet Recovery to do the OS install. That's factory fresh right there, my friend. The only thing it won't have after all that is the new computer smell.

  • thank you very much for your answer, as mentioned I tried everything, even the diskutil zeroDisk command, but I always get the "couldn't unmount", and I don't really know what to do, I cannot use my mac :c – Marcelo Tataje Jun 20 '14 at 7:44
  • If it won't unmount the volume then it can only mean that you're somehow booted off it. That's why I am curious where you got that Lion boot CD, since Apple never distributed it on physical media and burning one yourself requires a dual layer disc. Have you tried the Internet recovery option? You can boot from that by holding down Command+Option+R while powering on. If it still says the volume can't be unmounted after that, you may need to boot from a Linux Live CD or possibly extract the drive. – Wes Sayeed Jun 20 '14 at 8:13

It sounds like you are trying to rollback from Mavericks to Lion.

Your reasons are yours but the "Recovery partition could not be created" should not be the one.

If that is your problem then reinstall Mavericks using the cmd-r during start up, it is Mavericks that creates the Recovery partition on your hard drive. That partition is hidden partition.

If you want to do it your self (or it does not work) then follow those instruction (or other sources) how to install recovery partition.

If you still want to roll back see instructions here @ apple.stackexchange (or other sources).

  • Problem is that I can't perform any action on my MAC since I've never made a backup of anything. I just have the installation options and some installation utilities. In most of the links, they talk about deleting partitions and everything gets solved, I tried that but with no success because every single time I try to delete a partition it says: "couldn't unmount the volume". Even if I try to install Lion or Mavericks always says the same: Recovery partition cannot be created. I am not able to use the programs to create a recovery partition because I don't have options to download those files – Marcelo Tataje Jun 18 '14 at 12:25

Go to a friend using a similar mac.. Use a usb data converter to connect your hard drive. and clone this drive of yours with his. Of course all the materials in his drive will become yours. You need to erase them.Then you ..You are experienced now.. All the best Firts prepare the tools for your next formatting !

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