Cannot boot up from external with Snow Leopard installed

Question

Cannot boot up from external with Snow Leopard installed

I've got an iMac Intel Core 2 Duo running Tiger 10.4.11.

I've successfully installed Snow Leopard 10.6.3 onto an external drive (or so the screen said).

My mac recognizes the external drive as a start-up disk and allows me to select it as such. But upon restart, machine comes up in Tiger.

My external drive is brand new, OWC Mercury Elite AL Pro using a fire-wire connection. After installation but two failed attempts at start-up, I ran first aid on the external and no repairs were necessary. Using System Prefs I selected the external as my start-up disk, hit Re-start, but machine still restarts from Tiger.

The only other piece of information that may be vital, that I can think of, is that I misunderstood the "Mac readiness" of the drive when I took it out of the box. I first erased it (unnecessarily). Then I discovered this mistake, and made a point to re-format it using the GUID partition setting. Computer claimed that installation was successful upon installing Snow Leopard.

But now, machine will not start up in Snow Leopard.

iMac (20-inch Mid 2007), Mac OS X (10.4.11), 20-inch, 4 GB 667 MHz DDR2 SDRAM

Posted on Mar 14, 2012 4:34 PM

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Answer 1

BDAqua

Level 10

239,147 points

Mar 14, 2012 9:13 PM in response to Ernie Centofanti

Hold the Option/alt Key down at startup & try to choose the External drive.

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Answer 2

Mar 14, 2012 9:39 PM in response to BDAqua

OK, I held down the Option key at startup, and only a single icon representing my internal drive appeared, with an arrow underneath it. The external drive icon did not appear. I tried twice. Maybe I didn't wait long enough for the second drive to appear?

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Answer 3

BDAqua

Level 10

239,147 points

Mar 15, 2012 1:11 AM in response to Ernie Centofanti

You can try he 3/4 circle to have it scan for drives agin, but I think yjis is some other problem.

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Answer 4

Lexiepex

Level 6

14,102 points

Mar 15, 2012 2:35 AM in response to Ernie Centofanti

obviously the external drive is not bootable. It may contain Snow Leopard succesfully but it is NOT bootable.

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Answer 5

Limnos

Level 10

411,187 points

Mar 15, 2012 7:47 AM in response to Ernie Centofanti

I have no idea if this has anything to do with it but check if there are firmware updates: http://support.apple.com/kb/HT1599

If it was any other brand drive I'd say it was a problem with the enclosure, but OWC is supposed to be pretty reliable in making sure its gear is compatible with Macs.

You installed Snow Leopard from a retail version disc and not a disc that came with another Mac?

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Answer 6

Mar 15, 2012 8:36 AM in response to Limnos

Limnos, I installed Snow Leopard from a retail disc I purchased on eBay, and came to me never used and still in the shrink wrap (no, it did not com with another Mac).

I checked into the firmware updates, and my computer informed me that it did not need the EFI Update

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Answer 7

Limnos

Level 10

411,187 points

Mar 15, 2012 11:16 AM in response to Ernie Centofanti

Double check. GUID, HFS+ journaled?

Since you can select the item in System Preferences it sounds like it is being recognized as a valid boot drive when the computer is up and running, yet it does not seem to be detected at startup. If this computer was 10 years older I'd have a list of things to try. 🙂

What to do if your computer won't recognize a FireWire or USB device - http://support.apple.com/kb/HT1317

Is this one of those models you can also connect with USB?

I could take another wild guess and: Intel-based Macs: Resetting the System Management Controller (SMC) - http://support.apple.com/kb/ht3964

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Answer 8

Mar 15, 2012 11:16 AM in response to Ernie Centofanti

OK, here's where I am now. Using CCC, I cloned my hard drive and Tiger OS to the external. I am unable to boot up in Tiger from the external, despite selecting it using System Prefs-->Startup Disc. Holding down the option key while starting up gives me only one choice of startup disc, the main hard drive.

So if something is wrong with the enclosure of the external, what next?

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Answer 9

Limnos

Level 10

411,187 points

Mar 15, 2012 11:19 AM in response to Ernie Centofanti

So if something is wrong with the enclosure of the external, what next?

My edit and your post coincided. 🙂

Try the SMC reset. If that doesn't help then get on the phone with OWC and see what they recommend. You're kind of in a tricky situation because it isn't like the enclosure is not working at all.

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Answer 10

Mar 15, 2012 11:19 AM in response to Limnos

Limnos: yes, my external can use either firewire or USB. Right now I've got it connected with firewire.

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Answer 11

Limnos

Level 10

411,187 points

Mar 15, 2012 11:19 AM in response to Ernie Centofanti

Try USB

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Answer 12

Mar 15, 2012 11:42 AM in response to Limnos

OK, I switched to a USB cable and that worked! I have now started up in Tiger on the external. I checked. This time it allowed me to select the external after holding down the option key. Also, I did About This Mac, and it shows my external as the startup disk. Success!

Now, how do I change the Tiger on my external to Snow Leopard?

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Answer 13

Limnos

Level 10

411,187 points

Mar 15, 2012 12:01 PM in response to Ernie Centofanti

Probably some quirk about that enclosure's chipset. Remind me not to get one if that's the case because I can only boot Firewire.

Either that or they took out FW bootability when they brought in USB bootability with Intel Macs, but I have never used an Intel Mac so I don't know about that. It would surprise me (no, I take that back, nothing Apple does to "improve" things surprises me now).

Now erase the drive and try over again with SL.

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Answer 14

Mar 15, 2012 11:59 AM in response to Limnos

OK. Erasing drive and starting over again.

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Answer 15

BDAqua

Level 10

239,147 points

Mar 15, 2012 12:37 PM in response to Limnos

My IntelMac boots 10.5. 10.6, 10.7, & beyond using FW Drives just fine, (including OWC Mercury Elite AL Pro)... except for the fact that Apple did do something to FW in 10.7 & up anyway, because the same FW800 drives will only operate at FW400 speeds if there's even a FW400 cable dangling from one or the Mac itself, it also seems to slow USB2 on some devices to USB1.1 or 2x USB1.1 speeds!???

I'm wondering about the FW cable here.

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