I've got a working bootable mavericks thumb drive, but I haven't the installer from Mac App store...

Can I upgrade from mountain lion to mavericks doing the installation from usb drive or must I do a clean install?

Can I boot from usb drive and upgrade, or when I boot from usb I'm forced to format and do a clean installation?

  • 1
    that should work ! either way.
    – Ruskes
    Jan 12, 2015 at 22:55
  • I confirm Buscar's answer: I made it more than 5 times on different Mac without a trouble.
    – dan
    Jan 12, 2015 at 23:16

1 Answer 1


Yes, simply run the installer from inside your existing OSX install.

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