How to boot from ext ssd?

[bobby68]

I installed Catalina on my external ssd on my MacBook Air 2014 and can boot fine.
But when I connect the ssd to my Mac Mini it can’t boot. When I use disk utility on the Mini it can see the ssd but it can’t see the Catalina portion.
On the Air in disk utility it shows up fine.

I used to run Catalina perfect from the ssd on the Mini but tried to upgrade to Big Sur which went horribly wrong, so I had to install from scratch, which I had done before. But now I can’t get it to boot.

Any suggestions?

 

[chrfr]

I installed Catalina on my external ssd on my MacBook Air 2014 and can boot fine.
But when I connect the ssd to my Mac Mini it can’t boot. When I use disk utility on the Mini it can see the ssd but it can’t see the Catalina portion.
On the Air in disk utility it shows up fine.

I used to run Catalina perfect from the ssd on the Mini but tried to upgrade to Big Sur which went horribly wrong, so I had to install from scratch, which I had done before. But now I can’t get it to boot.

Any suggestions?

What year is your Mini?

 

[bobby68]

What year is your Mini?

2014 same as my Air

 

[BrianBaughn]

Have you tried installing Catalina on the external SSD connected to the Mini and then seeing if it will boot on the MBA?

 

[CoastalOR]

What macOS do you currently have on the 2014 Mini (it has to be High Sierra or newer to see the Catalina APFS format properly)?

 

[wellander1]

Try to use the option key right after you hear the startup chime.

 

[bobby68]

Have you tried installing Catalina on the external SSD connected to the Mini and then seeing if it will boot on the MBA?

Yes. Before I ran Catalina from the external ssd, the internal disk on the Mini didn’t and don’t have an os installed.

I have tried to install Catalina from the recovery on the mini on to the ssd, but it says it have to confirm my Mac or something, and when I press OK nothing happens.

I have installed the os on the ssd from my Air before, to use on the mini, but this time I’m stuck.

 

[bobby68]

What macOS do you currently have on the 2014 Mini (it has to be High Sierra or newer to see the Catalina APFS format properly)?

I don’t have macOS on the mini’s internal disk, I ran it from the ssd before. The internal disk is used for storage of music an pictures.

 

[bobby68]

Try to use the option key right after you hear the startup chime.

I did that several times, but can’t see the macOS on the ssd. I run disk utility and can see the ssd, but it seems empty - no partitions or anything.

when I start my Air with the option key and run disk utility, I can see the ssd AND the partitions containing macOS and data.

And I can boot my Air from the external ssd fine with the option key so I don’t get why my mini can’t see macOS on the ssd.

 

[chrfr]

I did that several times, but can’t see the macOS on the ssd. I run disk utility and can see the ssd, but it seems empty - no partitions or anything.

when I start my Air with the option key and run disk utility, I can see the ssd AND the partitions containing macOS and data.

And I can boot my Air from the external ssd fine with the option key so I don’t get why my mini can’t see macOS on the ssd.

If you have never run the Catalina installer from that computer, it's missing firmware updates which it probably needs to run Catalina. You may be able to resolve this by making a USB installer, starting up the mini from that and then reinstalling Catalina on the external drive.

 

[bobby68]

If you have never run the Catalina installer from that computer, it's missing firmware updates which it probably needs to run Catalina. You may be able to resolve this by making a USB installer, starting up the mini from that and then reinstalling Catalina on the external drive.

I’ll try that. Thanks.