Change boot priority

[Martini1991]

I'll start this by saying I'm not exactly to grips with MacOS.

I literally just use my iMac to watch content on.

It's a 27" late 2013 iMac with a USB Blu-ray drive and an external USB SSD.

I have my OS installed on the external USB SSD and it's been running fine for ages, however with a MacOS update a little while ago, it defaults to booting up my Blu-ray drive and I end up with just a folder icon with a question mark.

If I pull out the drive then turn on the Mac, then it'll boot into the OS fine.

How on Earth do I change it so it just works like it's meant to, without continuing to take out the drive? I want to just leave it in.

Cheers.

 

[Captain]

Press and hold the option/alt key when powering up, this lets you select the boot option.

Also inside macOS:

Click on the Apple menu and select "System Preferences," then select "Startup Disk."

Select your USB drive.

 

[Martini1991]

Press and hold the option/alt key when powering up, this lets you select the boot option.

Also inside macOS:

Click on the Apple menu and select "System Preferences," then select "Startup Disk."

Select your USB drive.

On the start up disk, it doesn't show my external USB blu ray drive, only my external SSD.

That still results in the issue with the external blu ray drive connected.

It was working fine for ages, and then when it came back on a software update it was stuck until I moved out the blu-ray drive.

It's never been right since and resulting in me taking out the drive until needed.

 

[Captain]

When you click system preferences and start up disk, is the padlock in the corner locked? It needs to be unlocked in order to make changes.

 

[Martini1991]

When you click system preferences and start up disk, is the padlock in the corner locked? It needs to be unlocked in order to make changes.

There's nothing to change.

My drive's in, as on the "desktop" it's there with my constantine blu-ray in.

 

[Captain]

Ok let me do some digging.

 

[Martini1991]

Ok let me do some digging.

Cheers.

It sounds like such a simple issue lol, so frustrating.

 

[Martini1991]

I've tried a wipe of both my external SSD and internal HDD and reinstall of Catalina, and then as soon as my Blu-ray external is plugged in it won't boot lol.