How to restore from Time Machine WITHOUT install discs using a second Mac

It's a question that is asked repeatedly all over the web by Mac users like me that bought in to Time Machine (TM) on the assumption that if their computer died one day it would be a piece of cake to restore from it, only for that day to come and then to be told "ahh, okay the first thing is to get your computers install discs..." (loud crashing sound of world falling around ears).

I've never been able to afford a new Mac and both of my machines were bought second-hand. Neither came with Leopard (both have Tiger and have been upgraded to Leopard via the net). This was never supposed to be a problem as I've been backing up with TM. However it appears that Tiger discs are as much use as an inflatable dart board when it comes to using TM. So I've been faced with the possibility of having to spend £130 (about two hundred Pres Sheets, Yankees) on the Leopard install discs just so that I can have the option of restoring from TM. Bonkers.

However after much nashing of teeth, a very long weekend learning all sorts of things about 'Target Mode', 'Single User Mode', 'Verbose Mode', 'Open Source 9' etc the following solution has worked without the need to go out and buy those over-priced discs...

What you will need:
1 broken Mac requiring restoration
1 second donor Mac running Leopard (or Snow Leopard so long as the broken Mac can run it)
1 firewire cable with the correct fitting at either end to attach both Macs together
1 Time Machine backup

Note: The following is for when you have given up trying to boot from your hard drive. In my case I couldn't boot in to Safe Mode etc. so was forced to format my drive and re-import everything. If you've read this far I'm assuming your at the same point as well and have tried everything else that's out there first.

Also - both my Macs are Power PC's so can't run Snow Leopard, so I can't say 100% this will work with SL (Intel) machines. From what I've read Snow Leopard will work with this procedure too, but if you've found differently please feel free to add your experiences below...

STEP ONE: Format the corrupt Hard Drive or replace with a fresh HDD
*Link the two computers with a firewire.
*If you're replacing your HDD, remove your corrupted hard drive from the 'broken' machine and insert a new one.
*Power up the broken Mac whilst holding down the 'T' key. This will start it up in Target Mode and you'll get a nice firewire symbol floating around that machine's screen.
*Power up the second 'healthy' Mac. This will be our 'donor' machine. When it starts up after a few seconds you will see the hard drive of the broken Mac appear on the donor Mac's desktop.
*Using your donor Mac's 'Disc Utility', format the broken Mac's hard drive (now's the time to partition it etc. if you want to).

STEP TWO: Clone your donor Mac
Your broken Mac is no longer broken and now needs a new OS. But you don't have the discs, right? Well get this... you can clone your donor mac on to your machine, even if they are totally different i.e. a laptop on to a tower.
*Again using Disc Utility, click on your donor Mac's hard drive. The restore tab appears as an option.
*Click on restore and drag the donor Mac's hard drive that contains the operating system in to the Source box.
*Drag the newly formatted hard drive on the broken Mac in to the Destination box.
*Click restore. Your donor Mac's hard drive will now be 'cloned' on to your no-longer-broken Mac. Once this is done, eject the first Mac's hard drive from your donor Mac's desktop. You no longer need the donor Mac.
Ta daa! Your machine now starts up happy and smily again. Time to restore all that stuff that's been sat on your Time Machine drive...

STEP 3: Restore from Time Machine using Migration Assistant
This is the really clever part that prompted me to write this piece in the first place. Time Machine IS accessible without those Leopard install discs you don't have. You need to use something called 'Migration Assistant'.

*Start up your machine as normal and you'll see it is an exact clone of the donor machine. Weird huh?
*Attach your Time Machine hard drive. It will show up as an icon on the desktop and because of it's size, you'll be asked if you want to use it as a Time Machine backup. Err, NO YOU DON'T! Click 'cancel'.
*Open Migration Assistant (if you can't find it just type it in to Finder and click). There are three options, the middle one being to restore from TM or another disc. Yup, you want that one.
*Migration Assistant will now ask you what you want to restore in stages, firstly User Accounts, then folders, Apps etc. It will even import internet settings 🙂

And that's you done. Let Migration Assistant do it's thang... altogether I had about 140gb to restore, so it wasn't exactly speedy. This wasn't helped by the fact that my TM hard drive is connected via USB (yes, I know). Just leave it alone and it'll whirr happily away...

Before I go - you don't have an option of when to restore from, and will restore from the last Time Machine save. At least then you should be able to access TM and go 'backwards' if you need to.

Also - for a Mac expert, the above will be up there with 'Spot Goes To The Farm' in terms of complexity. However, for the rest of us the above is only available in fragments all over the net. By far the most common response to 'how do I restore from Time Machine without install discs' is 'you can't'. If I'd found the above information in one place I could have saved a lot of hair pulling and swearing over the last couple of days, so forgive me for sharing this workaround with the rest of the world. Meanwhile your expertise will come in very handy for the inevitable questions that will get posted below, so please feel free to help those people that won't be sure if this solution is the right one for them. I'm no expert, I just want to help people that were stuck in the same situation (and looking at the web, there's a LOT of them).

Hope this is of use to someone, thanks and *good luck*!