<< Solved >> Dell Optiplex 790 - Can’t get Catalina to Boot from External Drive.

[Axintosh]

Hi all,
This is my first build so forgive me if I miss any info you need.
I managed to get as far as installing Catalina onto an external 500GB USB drive. Trouble is I cant get it to boot from it.
I installed UNIBEAST in Legacy which was the only way to get it to start up and install.
Installing Catalina onto the external USB drive went smoothly.
Now I’m not sure how to get it to boot from the external USB drive.
In the BIOS that last thing I tried was moving USB Storage Device to the top of the Boot Sequence. Any help would be awesome.

Side Notes: Not that it matters but when I boot in Windows 10 it doesn’t see the 500GB external USB at all.
I’m currently waiting for delivery of the following SSD - Crucial 120GB and a GPU - 1GB AMD RADEON HD 6450.
Maybe I should wait until I get the SSD.

Any help would be awesome.

Cheers
Alex

 

[Axintosh]

I missed a step in the installation. I am also installing again onto the Main C drive. Which mean no more windows. So sad.

 

[flatlander48]

This should be in the Catalina section, not the Sierra section...

 

[Ilikeboth]

Did you get anywhere? I just picked up a 790 i plan on installing Catalina on, aside i cant get the usb drive made, it will make a sierra bootable usb no problem.

 

[trs96]

i cant get the usb drive made

What are you using to make the USB installer ?

 

[Ilikeboth]

I was using unibeast, but it never got past copying files even after 2 hours. I attempted, install disk creator, to install clover on the usb after but it wont let me select my usb drive, it says i can only install it on a Mac OS X device.

 

[trs96]

I was using unibeast, but it never got past copying files even after 2 hours. I attempted, install disk creator, to install clover on the usb after but it wont let me select my usb drive, it says i can only install it on a Mac OS X device.

What kind of computer and OS are you using to create your installer USB ?

 

[Ilikeboth]

Mid 2012 macbook pro, running catalina 2.5ghz dual core i5 processor and 8gb of ram. thanks

 

[trs96]

Did you disable SIP first before doing anything else ? Shown at 1:15 timestamp.

 

[Ilikeboth]

I did see that, but did not realize it was for everything Catalina, i have disabled it and am currently making a new usb, i am using legacy boot, for the optiplex 790. i did do a hachintosh on the optiplex 780 many years ago so i am relearning everything. thanks again for the help.