# bypass dead imac hard drive and boot from external hard drive?



## daveb123 (Jul 8, 2009)

My imac G5 isight's hard drive is dead. I would like to install OS X on an external hard drive and just use that as the hard drive for this machine. My questions are:

Can I boot from an external hard drive via USB and just run everything off the external hard drive? If so, how should I format the external hard drive so that it can be selected and written to when I boot from the install cd? The external hard drive I would like to use is a 75 gig Acom. I've tried booting from the install cd, and it either won't even find the external hard drive, or, when it does, it says it can't write to that external hard drive.


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## ElDiabloConCaca (Jul 8, 2009)

You probably need to format the external drive first.  Launch "Disk Utility" (in the "Utilities" menu after you select a language when booted from your OS X install CD/DVD) and highlight your external hard drive.  Click the "Partition" pane, select 1 partition (or whatever suits your fancy), then select "Mac OS Extended (Journaled)" and click "Partition".

Quit Disk Utility, and the disk should now show up as a valid install location.

Be aware that this procedure erases everything on the external hard drive, so ensure that the data that is currently on the external hard drive is backed up somewhere else.


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## daveb123 (Jul 8, 2009)

Thank you. I tried that already, and when I reformatted the external hard drive as Mac OS Extended (Journaled), the external hard drive wouldn't show up at all. Any other ideas?


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## ElDiabloConCaca (Jul 8, 2009)

Instead of doing a "reformat," try a "repartition" -- highlight the hard drive, click the "Partition" pane, select your partition scheme and disk format (Mac OS Extended), then click the "Options..." button at the bottom of the window.  Ensure that "Apple Partition Map" is selected in that "Options..." window.


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## daveb123 (Jul 8, 2009)

Still no dice. A little more background info, this Acom drive I am trying to use was the only DiskWarrior could find when I was salvaging my data from this imac. It wouldn't find the two Western Digital drives or the Vantec NexStar either. So I know it can be found. After using it to transfer all my files from DiskWarrior, I decided to use it as the external boot drive and didn't think it needed to be reformatted because DiskWarrior had found it. I booted the imac using the install disk, and the Acom couldn't be found. I've tried reformatting a couple of different ways (what you've just suggested, along with two partitions, one os extended (journaled) and the second partition ms-dos, just taking shots in the dark. Any other suggestions?


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## ElDiabloConCaca (Jul 8, 2009)

Strange... I know that PowerPC-based Macs cannot boot from USB devices, but apparently, Leopard changed that and now they can.

Is the drive USB or FireWire (or both)?  If both, try connecting it via FireWire (or if you have a FireWire drive laying about, try that one).


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## daveb123 (Jul 8, 2009)

actually i'm still using 10.4 for this imac, and i've been trying to connect via usb. i'll try firewire.


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## ElDiabloConCaca (Jul 8, 2009)

Ah, yes, with that combination (10.4 and PowerPC), USB booting may not be possible.


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## Jesse714 (Jul 8, 2009)

I did a little looking around on some forums from google searching, After i used my HP external to boot from, I've heard some people say that booting tiger it worked for them. Put the disc in your external, and turn the computer off. push the power button and hold the option key on start up, Let it sit there and process, It seems like the PPC startup disk-section takes way longer than the Intel Macs. You'll see your hard drive, and hopefully it'll bring the disk up. If it does, open disk utility and format your external to Mac OS (journaled). And that might work.

I've never tried it on Tiger, so i couldn't tell you if it works or not, I've only done it with a PowerBook G4 that already had Leopard on it, I just did a fresh install on it.

Good Luck


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## Jesse714 (Jul 8, 2009)

You may want to just look into buying a small hard drive (30-60) And then using your external to save your app's and movies on.

http://www.newegg.com/Store/Category.aspx?Category=15&name=Hard-Drives

These guys are really reasonable.


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## daveb123 (Jul 8, 2009)

that looks like what i'll have to do. how do i know if a hard drive is mac compatible? are they all and just have to be formatted? i read in a forum somewhere that hitachi drives are excellent replacements. true? what about this one?

HITACHI Deskstar P7K500 HDP725050GLA360 (0A35415) 500GB 7200 RPM 16MB Cache SATA 3.0Gb/s 3.5"

http://www.newegg.com/Product/Product.aspx?Item=N82E16822145215


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## Jesse714 (Jul 8, 2009)

Nope, Any one of those hard drives can be formated for you mac, just make sure that you get the right connection, either SATA or IDE. It looks like you have a good sata hard drive picked out. 
Newegg shipping, only takes like 2 days, even though it says 4-5, i got mine in 2 days, and pretty much everything has free shipping too. Its a great place for every computer part.

That's a 500 gig for 50 bucks, you honestly can't beat that, if you look on the first page that comes up, theres a 1T for 99


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