System doesn’t recognize APFS volume as startup disk

I installed Monterey on an APFS volume (I’m using Mojave on a 2015 iMac)

Actually, I installed Catalina, on the volume, then upgraded to Monterey. It rebooted and ran fine.

I rebooted into Mojave, and received a message, in the Mojave Finder, about a disk incompatiblity.

On my desktop (I have all my volumes displayed on my desktop), I have two new volumes - the expected Monterey volume, named Monterey - data, and another named “Update"

I ran Disk Utility on all three volumes but Monterey does not appear as a startup volume.

Any info appreciated...

iMac Pro

Posted on Apr 9, 2022 9:56 AM

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Question marked as Top-ranking reply

Posted on Apr 9, 2022 4:06 PM

Matti Haveri wrote:

> Mojave Finder, about a disk incompatiblity

This is normal because Mojave does not fully understand the new system & data APFS volumes.

Mojave Startup pref might not support newer macOS so Option-boot to select them.

Thank you, Matti Haver - this solved my problem. I was able to select MontereyOS by Option-booting.

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Question marked as Top-ranking reply

Apr 9, 2022 4:06 PM in response to Matti Haveri

Matti Haveri wrote:

> Mojave Finder, about a disk incompatiblity

This is normal because Mojave does not fully understand the new system & data APFS volumes.

Mojave Startup pref might not support newer macOS so Option-boot to select them.

Thank you, Matti Haver - this solved my problem. I was able to select MontereyOS by Option-booting.

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System doesn’t recognize APFS volume as startup disk

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