MP 1,1-5,1 Mac pro 5.1 wont boot installer

[waiser]

HI there. I have a 5.1 running Mojave on a Pcie Nvme card. I want to run El Capitan on a SSD in one of the 4 open Sata Bays to run legacy apps. I have a bootable back up of my El Capitan on an external SSD. I just cant seem to get the machine to boot up in the El Capitan USB bootable installer that i made. It shows up in the start up disc but when i restart and choose that it just doesnt boot up. Is there another way to do this. I was going to install El Cap on the new SSD and then use migration assistant to bring everything over from my carbon copy cloner back up. But this back up is bootable too. Can i just clone the new drive instead?

thanks in advice for any help.

 

[theMarble]

What did you use to make the El Capitan installer?

Slightly off topic here but also just so you know, your NVMe drive will not be detected by El Capitan as PCIe NVMe connections wouldn't be supported until High Sierra came out.

 

[waiser]

What did you use to make the El Capitan installer?

Slightly off topic here but also just so you know, your NVMe drive will not be detected by El Capitan as PCIe NVMe connections wouldn't be supported until High Sierra came out.

i used diskmaker.

 

[theMarble]

i used diskmaker.

Never use any third-party tools for creating OS X installers.

Install OS X El Capitan.app comes with a tool called createinstallmedia, which is the proper way to make a USB.

Create a bootable installer for macOS - Apple Support

You can use a USB flash drive or other secondary volume as a startup disk from which to install the Mac operating system.

support.apple.com

 

[h9826790]

Is there another way to do this.

Why don't you simply boot El Capitan, then run the installer, and select one of the internal drive as target drive.

 

[waiser]

Why don't you simply boot El Capitan, then run the installer, and select one of the internal drive as target drive.

do you mean boot from the carbon copy cloner external bootable back up?

 

[h9826790]

do you mean boot from the carbon copy cloner external bootable back up?

Correct, if you can boot to that external El Capitan SSD. Just boot to desktop and run the installer, then you can select the target drive you want.