I am trying to install OS X 10.7 x64 on my Intel Core 2 Duo MacBook Pro from 2007. Before I was running OS X 10.6.8 x64 which worked fine, but I can't seem to install 10.7 as 64-bit. Somehow it assumes under the installation that it must be x86, since I am not asked which version I want to install.

Apple states that it should be able to run 64-bit (and since Snow Leopard was x64 I don't doubt it).

I have checked for any firmware updates, but all seems to be up to date.

How can I get my machine to install the x64 version? Is there some way to force it?

  • what error do you get ? Commented Sep 24, 2013 at 9:45
  • I don't get any error as such. It just installs the OS as x86.
    – Severin
    Commented Sep 24, 2013 at 9:45
  • Then, why do you say it doesn't install the 64 bits version ? Where do you get this statement? Commented Sep 24, 2013 at 9:47
  • "uname -a" states "root:xnu-1699.32.7~1/RELEASE_I386 i386", which indicates a 32-bit Kernel.
    – Severin
    Commented Sep 24, 2013 at 9:52

1 Answer 1


Your MacBook Pro has indeed a 64 bits processor but it has a 32 bits EFI. So without a hack you won't be able to boot the 64 bits kernel. (source)


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