Chosen Solution
My MacBook Pro 2015 13" stopped booting. My last backup is too old so I bought and OWC Envoy Pro Enclosure to retrieved data. The only other Apple machine that I can use is an iMac 27" 2012. I put my disk in the enclosure and plugged it to the iMac. However, I can’t see the files. In “disk utility”, I have 3 new partitions: “disk3s5”, “Macintosh HD - Data” and “Update”. The first one is always greyed. In the Finder I can only see the files from the partition named “Update”. If I try to access the main partition, it doesn’t stop loading. I tried to edit “/etc/fstab” with “UUID=my_uuid none apfs rw,noauto 0 0” but nothing changed. I also tried “defaults write com.apple.frameworks.diskimages skip-verify YES”.
Ah! You hit the File System mis-match issue! Your two systems have different OS’s Your 2012 iMac likely has Sierra or older which is HFS+ based and your MacBook Pro is likely using Hight Sierra or newer which is APFS based. Basically, your iMac can’t access the newer file system and it also can’t boot from it either as the systems firmware is not updated to support it.
