Banging my head against the wall on this one, but will keep testing/researching here. If somebody has a quick fix for me, or quick reference, I'd be most grateful:
I have a utility Mac Pro 2009 that has multiple systems installed on multiple volumes. I usually run a macOS 12.7.6 Monterey system via OCLP on it, but I needed to test something out in 10.13 High Sierra the other day. Now I can't get it back into Monterey. Boot picker is fine, but when I choose the Monterey system, I get the "International No" symbol and "support.apple.com/mac/startup". And the boot picker icon circle does not show the red & blue Monterey scheme, but rather the mountain from High Sierra. I can (and have) reinstall Monterey on a new volume, which works, but I can't get the existing 2 Monterey volumes to boot.
In the photo, the main system is "MacPro SSD 12a", but the "Monterey Rescue" also will not work. As you can see, they both have "- Data" on the end and the High Sierra mountain thumbnail.
Fouled up APFS containers or system/data pairs? I have tried over-installing Monterey on the main volume I need, to no avail. What else can I try AND how do I avoid this hiccup if I need to change systems again?
Thx,
Fred


I have a utility Mac Pro 2009 that has multiple systems installed on multiple volumes. I usually run a macOS 12.7.6 Monterey system via OCLP on it, but I needed to test something out in 10.13 High Sierra the other day. Now I can't get it back into Monterey. Boot picker is fine, but when I choose the Monterey system, I get the "International No" symbol and "support.apple.com/mac/startup". And the boot picker icon circle does not show the red & blue Monterey scheme, but rather the mountain from High Sierra. I can (and have) reinstall Monterey on a new volume, which works, but I can't get the existing 2 Monterey volumes to boot.
In the photo, the main system is "MacPro SSD 12a", but the "Monterey Rescue" also will not work. As you can see, they both have "- Data" on the end and the High Sierra mountain thumbnail.
Fouled up APFS containers or system/data pairs? I have tried over-installing Monterey on the main volume I need, to no avail. What else can I try AND how do I avoid this hiccup if I need to change systems again?
Thx,
Fred

