Stuck trying to install Catalina on external drive

[machenryr]

It’s not really an external drive. It’s a 1TB SSD PCIe. I formatted it APFS, downloaded the Catalina installer, I select the correct drive for installation. It proceeds. Says it’ll take 3 minutes. At about 2:45 minutes it says it cannot verify and the installer closes.

On the SSD I see macOS Install Data folder but it’s not bootable. What am I missing?

2019 Mac Pro 16 core 10.15.2

 

[machenryr]

Nobody? I don’t know what I’m doing wrong here. It appears to install but it’s not bootable. There’s an install data folder. It’s like it wants to verify the identity or owner or something.

 

[machenryr]

I've had big problems with the 7,1 MP. I am trying to fix it by installing a clean Catalina OS and loading one audio program at a time. But this install won't install. Nobody has a suggestion, ideas or can assist me?

 

[chrfr]

I've had big problems with the 7,1 MP. I am trying to fix it by installing a clean Catalina OS and loading one audio program at a time. But this install won't install. Nobody has a suggestion, ideas or can assist me?

Did you enable booting from external drives in the Startup Security Utility?

 

[machenryr]

OK. I just got off the phone with Apple Support. I CAN'T do what I'm trying to do! Because of the T2 chip, I cannot have two OSes internally. Argh.

 

[Fishrrman]

"OK. I just got off the phone with Apple Support. I CAN'T do what I'm trying to do! Because of the T2 chip, I cannot have two OSes internally."

What happens if you:
a. boot to the recovery partition
b. open Startup Security, and then...
c. DISABLE the t2 protection?

Suggestion 2:
If you want to experiment with Catalina, buy a cheap 128gb 2.5" EXTERNAL SSD, put it into a USB3 enclosure, connect it to the Mac, and install Catalina onto that. T2 problems... solved.