macOS no longer boots after shrinking a partition

[MrSLML]

On a late-2012 Mini, an APFS container held both Mojave and, via OCLP, Ventura. Linux was installed on a separate partition (Zorin). At startup, I was able to boot all three systems using the OCLP boot manager.

Then I had the (bad) idea to shrink the APFS container to make room for another partition for a test system. But the process failed. The new 50 GB partition was created (even though an other APFS instead of exFat), but I can no longer boot into either of the macOS systems. They no longer appear in the boot manager. Linux is the only option that appears on my screen, and it boots up without any problems.

First aid, using an (OCLP) Ventura boot stick didn’t work. I’ve now booted from an external hard drive (Sierra) to investigate further via the terminal:

disk0s02 was the APFS container containing the two macOS installations. The listed 825 GB is the new size after the reduction. I didn’t go all the way to the limit of the possible resize, that would have been 775 GB. So, resizing and creating a new partition worked, but the APFS containers no longer seem to be recognized.

How should I proceed? Is there still a chance to recover the systems and make them bootable again? Thanks for the help!

 

[Bigwaff]

First, you have to realize that APFS implementation in Sierra is initial preview implementation and so much older than the implementation in Ventura. If your APFS container and volumes were created using Ventura, I believe Sierra can't even mount them, so don't even try or you may bork them completely. You may need to install Ventura on external drive to truly troubleshoot this issue.

 

[carylee2002]

You may have a drive failing and may have to copy clone each drive to a external drive, then first aid each one individually it in safe mode to look for errors. Also why do you have 2 recovery HD in your external?

 

[capamac]

Partition resizing ... it always kinda weirded me out, so I avoid it.

Also this is why backups are a good practice and hopefully you have a backup.