macOS CatalinA -Who knows this message (hard disk utility first aid) - Warning: MT mapping is not completely referenced?

Greetings to you!

For now; hope you are all healthy !?

To my question:

1) Who knows this message (hard disk utility first aid) - Warning: MT mapping is not completely referenced?
Now had no (or only the usual Catalina) problems, but occasionally run first aid over it.
This message comes at "Container disc2" at the end of the check. The same when checking from "Fusion Drive". The same message comes.
With Macintosh HD 1 + 2 data - does this message not appear?

Couldn't find much about it on the net, tried some suggestions https://discussions.apple.com/thread/251159425 but didn't do anything. Ne reinstall. I still did before I don't know what that means - I have backups with TM anyway. That with the reinstall. was a recommendation to fix the problem - whatever the consequences could be ....?

2) Did someone check that with "first aid"?
3) If so. Does this message come from Erste H. only for "Container disc2" and "Fusion Drive"?

I found that after Catalina installation. Clean installation didn't help either?
I was unfortunately not able to load a ScreenShot ??

More discussions about the futility of this error: https://developer.apple.com/forums/thread/655840?page=1#738339022

I've been having random freezes on my 2017 iMac for the last few months and haven't been able to work out what's causing it. I ran Disk Utility and have the same problem as you guys.

Verifying the startup volume will cause this computer to stop responding.

Verifying storage system

Using live mode.

Performing fsck_apfs -n -x -l /dev/disk0s2

Checking the container superblock.

Checking the fusion superblock.

Checking the EFI jumpstart record.

Checking the space manager.

Checking the space manager free queue trees.

Checking the object map.

Checking the Fusion data structures.

Checking the encryption key structures.

Checking volume /dev/rdisk2s1.

Checking the APFS volume superblock.

Checking the object map.

Checking the snapshot metadata tree.

Checking the snapshot metadata.

Checking snapshot 1 of 2 (com.apple.os.update-731FFAAF9830B1760968C2024FB0914C3A062192BFA55CF51D7E07C223858619)

Checking snapshot 2 of 2 (com.apple.os.update-MSUPrepareUpdate)

Checking the extent ref tree.

Checking the fsroot tree.

Checking the file extent tree.

Verifying volume object map space.

The volume /dev/rdisk2s1 appears to be OK.

Checking volume /dev/rdisk2s2.

Checking the APFS volume superblock.

Checking the object map.

Checking the snapshot metadata tree.

Checking the snapshot metadata.

Checking the extent ref tree.

Checking the fsroot tree.

Verifying volume object map space.

The volume /dev/rdisk2s2 appears to be OK.

Checking volume /dev/rdisk2s3.

Checking the APFS volume superblock.

Checking the object map.

Checking the snapshot metadata tree.

Checking the snapshot metadata.

Checking the extent ref tree.

Checking the fsroot tree.

Verifying volume object map space.

The volume /dev/rdisk2s3 appears to be OK.

Checking volume /dev/rdisk2s4.

Checking the APFS volume superblock.

Checking the object map.

Checking the snapshot metadata tree.

Checking the snapshot metadata.

Checking the extent ref tree.

Checking the fsroot tree.

Verifying volume object map space.

The volume /dev/rdisk2s4 appears to be OK.

Checking volume /dev/rdisk2s5.

Checking the APFS volume superblock.

Checking the object map.

Checking the snapshot metadata tree.

Checking the snapshot metadata.

Checking the extent ref tree.

Checking the document ID tree.

Checking the fsroot tree.

Verifying volume object map space.

The volume /dev/rdisk2s5 appears to be OK.

Checking volume /dev/rdisk2s6.

Checking the APFS volume superblock.

Checking the object map.

Checking the snapshot metadata tree.

Checking the snapshot metadata.

Checking the extent ref tree.

Checking the fsroot tree.

Verifying volume object map space.

The volume /dev/rdisk2s6 appears to be OK.

Verifying allocated space. warning: MT mapping (0x4000000527315 -> 0x17e9ca7, 1, C) is not completely referenced warning: MT mapping (0x400000068df71 -> 0xaba486, 1, C) is not completely referenced warning: MT mapping (0x4000000e60d9d -> 0x1a91ec0, 1, C) is not completely referenced warning: MT mapping (0x400000141cf48 -> 0x16c0dff, 1, C) is not completely referenced warning: MT mapping (0x400000145de2f -> 0x16c27ee, 1, C) is not completely referenced warning: MT mapping (0x40000029ab1fd -> 0x174bbd5, 1, C) is not completely referenced warning: MT mapping (0x40000029af6e9 -> 0x174b567, 1, C) is not completely referenced warning: MT mapping (0x4000008793e8c -> 0xc28c85, 1, C) is not completely referenced warning: MT mapping (0x4000008a148b6 -> 0x138087, 1, C) is not completely referenced warning: MT mapping (0x4000008a7faa0 -> 0x79ec21, 1, C) is not completely referenced. . . . warning: MT mapping (0x4000009248436 -> 0x798388, 1, C) is not completely referenced warning: MT mapping (0x40000092b18c1 -> 0x174b5e6, 1, C) is not completely referenced warning: MT mapping (0x40000092b1f73 -> 0x174ad2e, 1, C) is not completely referenced warning: MT mapping (0x400000948629e -> 0x79eaf2, 1, C) is not completely referenced warning: MT mapping (0x40000094866bb -> 0x79ae98, 1, C) is not completely referenced warning: MT mapping (0x4000009498d63 -> 0x608034, 1, C) is not completely referenced warning: MT mapping (0x4000009702025 -> 0x1804c0, 1, C) is not completely referenced warning: MT mapping (0x400000978508a -> 0xbf7aff, 1, C) is not completely referenced warning: MT mapping (0x40000097bb03c -> 0x721196, 1, C) is not completely referenced warning: MT mapping (0x40000099bad22 -> 0xe585d0, 1, C) is not completely referenced warning: MT mapping (0x4000009aac1f5 -> 0x17e8a27, 1, C) is not completely referenced warning: MT mapping (0x4000009bbca59 -> 0x5dd8be, 1, C) is not completely referenced warning: MT mapping (0x4000009c7ee22 -> 0x17e8194, 1, C) is not completely referenced warning: MT mapping (0x4000009d41f6d -> 0x1b72805, 1, C) is not completely referenced warning: MT mapping (0x4000009e3c835 -> 0x60862e, 1, C) is not completely referenced warning: MT mapping (0x4000009e5e147 -> 0x4a9653, 1, C) is not completely referenced warning: MT mapping (0x4000009fb2a8c -> 0x183600, 1, C) is not completely referenced warning: MT mapping (0x4000009fc3bc3 -> 0xc28b33, 1, C) is not completely referenced warning: MT mapping (0x400000a1334da -> 0x15a47bb, 1, C) is not completely referenced warning: MT mapping (0x400000a174d3e -> 0x15a4838, 1, C) is not completely referenced warning: MT mapping (0x400000a18ef1f -> 0x17e83ba, 1, C) is not completely referenced warning: MT mapping (0x400000a1b81a0 -> 0x6e0105, 1, C) is not completely referenced warning: MT mapping (0x400000a1d8b95 -> 0x6e05ef, 1, C) is not completely referenced warning: MT mapping (0x400000a286518 -> 0x4a81d8, 1, C) is not completely referenced warning: MT mapping (0x400000a3267cc -> 0x16905af, 4, C) is not completely referenced warning: MT mapping (0x400000a365af5 -> 0x1b70046, 1, C) is not completely referenced warning: MT mapping (0x400000a9cd84b -> 0x798517, 1, C) is not completely referenced warning: MT mapping (0x400000ad2a3fe -> 0x181289, 1, C) is not completely referenced warning: MT mapping (0x400000ae3df9b -> 0x17a045c, 1, C) is not completely referenced warning: MT mapping (0x400000afb2fd6 -> 0x1808c7a, 1, C) is not completely referenced warning: MT mapping (0x400000afca6a7 -> 0x17a012a, 1, C) is not completely referenced warning: MT mapping (0x400000afce436 -> 0x17a1e1a, 1, C) is not completely referenced warning: MT mapping (0x400000b036d52 -> 0x10d00c6, 1, C) is not completely referenced warning: MT mapping (0x400000b2aa230 -> 0x1071e42, 54, C) is not completely referenced warning: MT mapping (0x400000b2ad6d2 -> 0x180b3a, 1, C) is not completely referenced warning: MT mapping (0x400000b2bf012 -> 0x79a129, 1, C) is not completely referenced Too many warnings of this type generated; suppressing subsequent ones. The container /dev/disk0s2 appears to be OK. Storage system check exit code is 0.

I think the takeaway here is the addition of the previously executed “but not stated”. Further Suppressed.

I've come to believe this was caused when I created a boot disc from a Carbon Copy Cloner clone instead of Time Machine. Just a theory, but for me it seemed to be the cause.

macOS CatalinA -Who knows this message (hard disk utility first aid) - Warning: MT mapping is not completely referenced?
 
 
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