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So, I've seen the many tutorials on how to extract the 'ESD' .dmg install DVD image from the App Store Lion installer, and burn to DVD or a USB stick etc, e.g.

http://www.eggfreckles.net/tech/burning-a-lion-boot-disc/

..and I've even tested my DVD out by booting from it, but I've not gone ahead with installing quite yet.

Just wondering, does anyone know if you can do an upgrade install from this DVD, or does that only become an option if you've followed the 'prescribed' method of running the App Store-sourced installer app directly? If you can upgrade from the DVD, what's the process? I'm finding:

a) it's not obvious from the initial menu when the install DVD boots how you'd select to upgrade, and b) all tutorials for installing using the burnt DVD only seem to mention doing an [erase, clean-install, restore from Time Machine or cloned backup] procedure.

Wisdom?

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3 Answers 3

Insert the DVD when logged in to your Mac and open the Finder. In the DVD, at top level, you will find an app called something like "Install Lion.app". Run it, and you will be upgrading your mac without losing data.

I don't know what happens if you boot to your DVD and run the installer from there.

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If it's anything like previous OS X DVDs, the "Install [version].app" is just a slightly more foolproof method of booting from the DVD. Even the App Store Lion installer does little more than copy the disk image to a hidden partition, then boot from it. –  Scott Jul 27 '11 at 7:50
    
Indeed, I'm aware this suggestion just ensures a reboot to the DVD (same as holding C on boot). –  Jonny Nott Jul 27 '11 at 10:04
    
So, I guess I'm asking .. when you reboot to the DVD and get to this screen: cultofmac.cultofmaccom.netdna-cdn.com/wordpress/wp-content/… .. what is then the process if you wanna just upgrade the existing Snow Leopard on your HDD to Lion (preferably without any 'restore' partition being created)? If you choose 'Reinstall Mac OS X', do you get an 'Upgrade Mac OS X on this disk' option like previous install DVDs? –  Jonny Nott Jul 27 '11 at 10:06

From what I've experienced, the Lion installer doesn't work like the Snow Leopard and previous versions did.

With Lion, you boot the DVD to perform a clean install. Same as before.

But, to do an upgrade, you just run the app off the DVD while booted into Snow Leopard. It will copy files over to perform the upgrade, then reboot and finish the upgrade. I've yet to see a way to boot off a Lion DVD and perform an upgrade.

You can remove the recovery partition after it's created, though I would leave it there just in case.

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This is not correct - you can do an upgrade-install when cold-booting to the Lion DVD, you just select the partition that has Snow Leopard on, and it'll automatically do an upgrade rather than a fresh install (although it gives you no indication that this is what it's doing, unlike previous installers). –  Jonny Nott Jul 29 '11 at 15:38
    
Oh, cool, that's good to know! Sucks that the Lion installer provides less detail than the installers before it. –  Collin Allen Aug 1 '11 at 1:59
up vote 0 down vote accepted

I've now tried this out for myself, using a spare HD.

As long as you have Snow Leopard already installed on the partition you want to upgrade, you can simply run the install DVD or USB stick that you've created, and select your SL partition and it will do an upgrade rather than a fresh install. It doesn't tell you this, but that's what happens. As always, make sure you have a full backup before doing it anyway!

Incidentally, even if you upgrade/install via this DVD/USB stick method that many people are talking about (by extracting InstallESD.dmg from the App Store download), it will still create a recovery partition during the install process, which is hidden in Disk Utility (but can, I believe, be removed via diskutil on the command line).

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