Can't see external drives in Startup Manager

[jjfelix]

My MacBook Pro 13" Mid-2012 running OSX 10.11.6 is not displaying externally connected disks in Startup Manager.

I have a brand new Crucial SSD cloned from a different machine, that I would like to boot from.

I know the SSD is fine as i've tested it externally with another almost identical MacBook pro (except running OSX 10.14.3) and have no problems getting it to boot.

I also know the USB ports on the machine are fine, as once logged in I can see other USB devices and hard drives in Finder, but NOT the Crucial SSD (although it is visible in Disk Utility). However, I can't see these other USB devices and hard drives in Startup Manager.

The Crucial SSD doesn't work when trying to boot it internally either.

I have tried resetting the NVRAM and SMC.

Below are screenshots from Disk Utility on the original MacBook (OSX 10.11.6), and then then working MacBook (OSX 10.14.3).

Is it perhaps something to do with how the Crucial SSD is formatted?

 

[CoastalOR]

I want to clarify if by "Startup Manager" you are referring to using the Option key during bootup?

I will say that El Capitan (10.11.x) will not be able to properly see bootable drives using the new APFS format (Mojave).

 

[jjfelix]

Yes that is correct.

To clarify also - the Crucial SSD has OSX 10.13 installed on it. Will this be incompatible with the OSX installed on the MacBook (10.11)?

 

[jbarley]

El-Capitan (10.11.6) cannot handle APFS volumes, a quick search comes up with links such as this...
https://discussions.apple.com/thread/8171271

if I have misunderstood your problem, just ignore this post.
a quote from the link above tells it all...
"By itself, El Capitan regards your APFS drive as a paperweight"

 

[Fishrrman]

If the Crucial SSD is formatted for APFS, the Mac with El Capitan won't "see it" at all.

Like it "wasn't even there".

 

[CoastalOR]

Yes that is correct.

To clarify also - the Crucial SSD has OSX 10.13 installed on it. Will this be incompatible with the OSX installed on the MacBook (10.11)?

Wow, the first post said nothing about 10.13, only 10.11 & 10.14. Regardless, 10.13 can be formatted as APFS. If that is the format on the Crucial, then 10.11 will not be able to properly see it.

 

[jbarley]

Your 2nd photo shows an external drive APFS, if that is the drive in question then all the info above about El-Capitan not seeing APFS drives applies, period!