upgrade Leopard to El Capitan bootable external HDD error iMac 2008

[jtdel99]

Hello all, I am a noob computer-fixer-upper for my dad for Father's day.

His 2008 iMac A1224 500Gb HDD was no longer functioning with Safari, making it useless. It is running Leopard 10.5.8. I want to update it to the highest supported OS which is El Capitan. Firstly, I upgraded the RAM from 1Gb to 6Gb. Now, I want to upgrade the OS.

Initially, It appeared I need to purchase (somehow) a Snow Leopard DVD and upgrade to that, then I could use the App Store to upgrade to 10.11 El Capitan. However, I came across the option of a bootable USB. I don't have a USB, so I decided to use a partitioned external HDD. I went into Terminal and got it to be bootable. Next, I restarted, OPTION, and got to boot screen, chose the bootable HDD labeled Install Mac OS X El Capitan. Things looked promising. Then, a circle with line through it ie. a "do not enter" symbol came up. Nothing happened, so it then finished by defaulting to boot to the main drive.

SO. Where am I going wrong? Is the fact that it is a partitioned HDD the issue? That's an easy enough fix. Or is there a way to just delete the old iMac disk and have the clean install of 10.11 over the erased disk? Is it an error because I only have Leopard? I backed up his data externally so erasing his disk is an option. Is the El Capitan download I have good to install over an empty disk or does it need to be installed over Snow Leopard at least? I downloaded El Capitan from Apple, and I also read about a clock issue, but seems that after Oct. 2019, the clock issue no longer pertains? Any guidance is appreciated. Thank you all.
-Jt

 

[superiska123]

How did you prepare the hard drive? Is the external hard drive partitioned as GUID or MBR? I'd also recommend getting a flash drive as they are quite inexpensive and you could at least rule the external hard drive as the cause of the issue.

You can also find bootable dmg images of Snow Leopard that you can burn to a double-layer DVD on the internet fairly easily (although the legality of this is, of course, questionable at best) in case it turns out that your computer just won't boot from an external drive.

edit: This is really only a bonus tip, which you might already be aware of but I thought I'd mention it: You could also replace the internal HDD for an SSD, which would drastically improve performance. It's not quite as straightforward as upgrading the RAM, though... But it would make the computer much more useable. IMO, OS X/macOS runs well on a hard drive only with releases up to (and including) Mavericks. All of the newere releases run noticeably slower on a traditional hard drive... Here's a guide: https://www.ifixit.com/Guide/iMac+Intel+20-Inch+EMC+2133+and+2210+Hard+Drive+Replacement/1008

 

[Fishrrman]

What kind of computer do you personally have?
Is it a Mac?
If it is, what OS is running on it?

 

[jtdel99]

Thank you for your reply. It is partitioned by GUID. I like the idea of the USB to just see if that is the issue. I would like to reserve the Snow Leopard DVD as the last possible avenue, understandably.

I also thought about upgrading the HDD to SSD. I have the tools to do so, however, I run into the same problem: how do I get El Capitan onto the new SSD? Get a SATA to USB cable, plug it into my macbook and somehow do it? I am afraid I would run into similar issues...
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What kind of computer do you personally have?
Is it a Mac?
If it is, what OS is running on it?

I have a late 2011 Macbook Pro running Sierra.

 

[superiska123]

Understandable concerns... Perhaps consider the SSD upgrade once you successfully install macOS on a hard drive?
One other thing I thought of was to try using the "Startup disk" option in system preferences to select the external HDD as your boot device.

 

[jtdel99]

Understandable concerns... Perhaps consider the SSD upgrade once you successfully install macOS on a hard drive?
One other thing I thought of was to try using the "Startup disk" option in system preferences to select the external HDD as your boot device.

Interesting. I will try this. Question before I do: So I change the startup disk to my external HDD. shut down, restart, and what if I get the same "prohibited" sign? How then do I change the start up disk back to the original internal HDD?

 

[superiska123]

I believe that your Mac would just boot into Leopard, just as it did before.

BTW, you should have the option to immediately reboot into the selected boot drive right in SysPref, no need to manually shut down and boot up again.

 

[jtdel99]

Interesting. I will try this. Question before I do: So I change the startup disk to my external HDD. shut down, restart, and what if I get the same "prohibited" sign? How then do I change the start up disk back to the original internal HDD?

I attempted, but the iMac Start Up disk utility in System Preferences does not even recognize the external as an option. Only the internal HDD.

 

[superiska123]

There you go, now we have narrowed down the problem to your external hard drive. Try reformatting it so the only partition is the macOS partition, or try using a flash drive. OR perhaps even try partitioning the iMac's built in hard drive and using the second partition as the boot volume.

 

[jtdel99]

Intriguing. I know how to reformat the external HDD to one partition. How would I do the partition on the iMac internal HDD? wouldn't that erase the entire internal disk? that's a bit intimidating if this still doesn't work..

 

[superiska123]

Here's a neat article explaining: https://www.peachpit.com/articles/article.aspx?p=1395749
You don't need to erase anything. If I were you, though, I'd probably spend $5 on a flash drive for convenience' sake.

 

[jtdel99]

I hear ya. Thanks for article. So I reformatted external HDD to 1 partition and it recognized it. Now installing El Capitan onto the internal iMac. we'll see if she holds!

If this works, and say I want to upgrade to a SSD internal in the future, would I use one of those SuperDuper or Cloner programs to migrate the internal HDD to the new SSD, then swap them out?

 

[superiska123]

You could, or you could put the empty SSD in place of the hard drive and install the OS from your external hard drive. And then transfer files from the old hard drive.

You could also put an SSD in place of the DVD drive if you don't utilize it and then you have more space, etc.

edit: Oh, or the easiest solution imho: Use external hard drive as Time Machine Backup device, reinstall Mac OS to the SSD from a flash drive, during installation select restore from Time Machine

 

[jtdel99]

Excellent. El Capitan is now running beautifully on this old iMac!

I like the Edit: Time machine backup option. That way I can start moving his files over to this updated iMac. Thank you very much for your help. God bless you! I hope this thread helps others in the future.

 

[superiska123]

Great! I am so glad I could help. Take care