Can't install MAC OS X Lion - Macintosh HD "This disk cannot be used to start up your computer."

****. That looks tough. I'll see. Thanks.

It's just a bit of work, but there's no magic involved, just Apple's tools. Migration Assistant works - and quite well too. Starting up from an external disk is as easy as holding down the Option key when the machine (re)starts; you'll get a screen with a disk icon per bootable medium - just click and away you go.

Yeah, I know. I'll see. Thanks.

It's a good idea to make an extra partition to store all important files, that way you can always perform a clean install only on OS partition without losing any data.

I dont know if you can upgrade you Leopard iMac with a Snow Leopard MacBook disc, i ignore if it has the neccesary drivers for your iMac. Just try it and let us know 🙂

I will.But first I'll do an external backup. Definitely. I will let you know. 🙂

MacAlbert wrote:

I would prefer not to a backup. My iMac, differently from my MacBook, has A LOT of files. Most of them (at least 90%) is very important. So, making a backup would take a lot of time.

If you don't back up at least your important files, you risk losing them. This does not apply just to upgrading the OS. All hard drives die eventually, & sooner or later yours will too. Even if it doesn't die before you quit using it, it may develop file system or other software related formatting problems that result in data loss.

When this happens, if you don't have a backup on another physically separate drive or on other media, that data will be gone forever.

So, do you know if could install Snow Leopard from the CD my MacBook Pro brought?

Grey system discs included with Macs are model-specific -- they won't install the OS they contain on any other model besides the one they come with. So if you have a Mac that did not come with Snow Leopard, you cannot use another model's Snow Leopard system discs to install it. You must buy a retail copy of Snow Leopard if you want to do that.

Oh… Do you know if they still sell a retail copy of Snow Leopard? Or if there is another way of updating Leopard to Snow Leopard?

Users getting the 'cannot be used' error may want to check out this KBase article.

It explains in detail how to do the resize trick already mentioned in this discussion & may be easier to follow than what we have said.

MacAlbert wrote:

Oh… Do you know if they still sell a retail copy of Snow Leopard?

As of this moment the Snow Leopard DVD is still being sold on the online US Apple Store (with a 2 to 4 week shipping date), & most likely is available in bricks & mortar stores that have sold it in the past. However, I have heard unconfirmed reports that once current supplies are sold out, Apple won't make any more of them, so if you want Snow Leopard I would not wait long to buy it.

Ok. Thanks again. If you know if there is any other way to install Snow Leopard (without doing a clean stall, I mean, updgrading, without having to format my disc) please tell me.

You don't have to format all the disk, only one partition for the OS to install. If you have enought space you can make another partition with Disk Utility and store there all the data you want to preserve (or move it to an disk), then, just run the Lion installer booting from DVD/USB and format only the Leopard partition, leaving the other untouched and all will be fine.

As some user said, sooner or later you will have to stop upgrading and upgrading without formatting because fragmentation in file system and/or damage in hard drive could waste all your important data.

MacAlbert wrote:

If you know if there is any other way to install Snow Leopard (without doing a clean stall, I mean, updgrading, without having to format my disc) please tell me.

The only time you have to reformat the drive to install Snow Leopard is if it is not formatted with the GUID Partition Table (GPT) partition format. Snow Leopard installers will not install that OS on a drive with any other partition format. If you have an Intel Mac, it came with the GPT format so if you have not reformatted the drive with some other format, you don't have to do this.

Assuming you have a retail Snow Leopard installer disc, the simplest way to upgrade from Leopard to Snow Leopard is just to follow Apple's instructions. This is not a "clean" install but it replaces all the old OS component files & the old versions of the apps that come with the old OS with new Snow Leopard versions, leaving your user files intact & your Mac ready to use the new OS without any migration hassles. It even uses the old stuff to decide what OS support files to install, which is one reason it results in a smaller OS footprint on your hard drive than the old OS had. For example, it won't install all the different language support files, just the ones for the language(s) you were using with Leopard. Some users report well over a GB of space freed up because of this.

Now that's interesting. I've done clean installs of 10.3, 10.4 and recently 10.6 - each time installing as few languages as possible. And each time I apply whatever update, I get the full bunch of language files it comes with installed as an unwanted bonus - the 10.5 upgrade on my bemissed 10.4.11 was no exception. I can hardly think of a more 'official' way to limit the number of localisations, but maybe there is?

The 10.6 installer is much different from earlier ones. There isn't even an "Erase & Install" or "Archive & Install" option, just one install option that is designed to use info from the existing OS (if it is there) to automatically adjust what it installs. You can customize what it installs, but that usually isn't necessary unless you do a "clean" install by erasing the startup volume beforehand, removing the info it will otherwise use for this.

Languages you use aren't the only thing it looks for. It will also look at the printers you use & by default only installs printer driver packages for them. If you have purchased a QuickTime Pro license, it will install Quicktime Player 7 (in the utilities folder) as well as Quicktime Player X (in the applications folder) & register your licence with the newly installed QT 7 Player app.

It even automatically runs the equivalent of Disk Utility's "Verify Disk" step before starting the install to make sure that files system problems won't affect the install, & -- if you begin the installation from the existing OS by launching the "Install Mac OS X" app -- uses existing OS network settings to "phone home" to Apple's database of incompatible software so any recent updates will be added to what is included on the DVD. If you start up directly from the DVD it won't do this, nor will it write a set of "preinstall" files to the drive that speeds up the install process & allows the installation to be aborted in the early stages without rendering the existing OS inoperable.

Hey guys,

So I also installed Linux (Ubuntu) on dual boot, and can't install Lion.

But the problem for me is that I need GUID as a partition scheme to install Lion,

and I have "MBR" instead (I have no idea why) :/

So I guess I have to find a way to switch to GUID ?

Any idea how can I do that ? (formating :/ ?)