MP 1,1-5,1 SSD not showing in Start-up Disk option.

[Kipsley]

Hey everyone. I'm running Mojave on my Mac Pro (early 2012) 5.1 machine.
I have three drives (all internal).
- 250 GB Seagate HDD. Bootable with latest Mojave on it.
- 250 GB SSD. Same as above.
- 1TB SSD. Same as above.

With all three drives in, how come only the 250 GB SSD is showing in the "Start-up Disk" option? The computer is also defaulting to this drive as the default start-up disk.
I need to change this as "Disk Utility" is telling me there is a corruption on this drive somewhere, where the other two drives have no issues. All I really want to do is to erase the 250 GB SSD and reclone it from one of the other drives, but first I need to get the machine to boot from one of the other drives.

 

[BrianBaughn]

Do you mean System Preferences>Startup Disk or the selection screen at Startup Manager when you boot holding down the Option key?

 

[bsbeamer]

GUID on all?

 

[Kipsley]

Ok. I now have 4 drives in. I managed to erase the data on the 250GB SSD. Now my computer has....
1 TB SSD as system disk running Mojave.
250 GB SSD as utility disk
1 TB HDD as Time Machine back up.
1 TB HDD that has my movie collection on it.

The 1 TB SSD with Mojave does not show up. system preferences > start-up disks.
It is seen if I boot up in recovery mode, and disk utility also sees it.

 

[KeesMacPro]

The 1 TB SSD with Mojave does not show up. system preferences > start-up disks.
It is seen if I boot up in recovery mode, and disk utility also sees it.

Could you open terminal enter: diskutil list
and post the screenshot?

Is Mojave installed natively or a patched version/ OC?