macOS Catalina - warning: MT mapping is not completely referenced

Question

harirajanv OP

Created Aug ’21

Replies 2

Boosts 0

Views 1.4k

Participants 2

macOS Catalina 10.15.7 software up-to-date. - Fusion drive. 27inch iMac Fusion drive. - 128GB SSD, 1TB HDD

I had these MT mapping errors, boot time to login into Mac taking 1hr. Even after login any click within the screen took another 30mins to responds to anything.

Checking DiskUtility, I see the below MT mapping warnings.

So as usual I tried to isolate the issue.

Boot from usb external drive to macOS Catalina had no issues at all.

Checked Apple Diagnostic - no errors found. So any hardware failure was ruled out.

SMART status of the disk also showed 'verified' so any disk issues ruled out.

ran Reset NVRAM or PRAM on your Mac. - no luck, issue the same.

ran Reset the SMC of Mac. - no luck, issue the same.

So finally decided to wipe clean the Fusion drive.

So ran he following.

diskutil resetFusion. - this was not needed, but did it anyway.

This created APS format

/dev/disk0 (internal, physical): of SSD disk 121GB

/dev/disk1 (internal, physical): of HDD disk 1TB

/dev/disk2 (synthesized): of the above two disk.

So went ahead and reinstalled macOS Catalina from network boot.

So far so good.

After that I ran Disk Utility and didn't see any such warning. Everything good so far. I was able to login fine under 30secs boot time to login.

So seemed all normal.

Then software update promoted, there are updates available. So went ahead and ran the update.

Login to Mac after that also was ok and under 30secs for boot time.

BUT when I ran the Disk Utility , I now started seeing the warnings again.

So it does seem software updates causing issues.

As of now able to login, but I am paranoid, the same cycle and steps as above I have done this three times. Slowly after couple of software updates, these warning message increase to the point where boot time increases to 1hr. Any action of mouse click takes another 30mins (yes literally)

Apple: can you please check - to me these seem to increase since the launch of M1 chip, so is the code for OS Catalina support having issues.

The volume Macintosh HD was formatted by diskmanagementd (1412.141.1) and last modified by apfs_kext (1412.141.2)

Checking the object map

Checking the snapshot metadata tree

Checking the snapshot metadata

Checking the extent ref tree

Checking the fsroot tree

Verifying allocated space

warning: MT mapping (0x40000002a8f5b -> 0x231f7d, 1, C) is not completely referenced

warning: MT mapping (0x40000002e954f -> 0xaaa777, 1, C) is not completely referenced

warning: MT mapping (0x4000000317c13 -> 0xad99e8, 2, C) is not completely referenced

warning: MT mapping (0x4000000317f57 -> 0xad9d1a, 1, C) is not completely referenced

warning: MT mapping (0x4000000317fd8 -> 0xad9d9c, 1, C) is not completely referenced

warning: MT mapping (0x4000000317feb -> 0xad9dae, 1, C) is not completely referenced

warning: MT mapping (0x400000031849b -> 0xad9f7b, 1, C) is not completely referenced

warning: MT mapping (0x4000000318513 -> 0xad9fea, 1, C) is not completely referenced

warning: MT mapping (0x4000000318524 -> 0xad9ffb, 1, C) is not completely referenced

warning: MT mapping (0x40000003187e6 -> 0xada261, 1, C) is not completely referenced

warning: MT mapping (0x40000003187e9 -> 0xada264, 1, C) is not completely referenced

warning: MT mapping (0x40000003187ec -> 0xada267, 1, C) is not completely referenced

warning: MT mapping (0x4000000318a7d -> 0xada5ca, 1, C) is not completely referenced

warning: MT mapping (0x40000003a0d2a -> 0x6a537b, 1, C) is not completely referenced

The volume /dev/disk1s2 appears to be OK

Storage system check exit code is 0

Finished file system verification on disk0s2

Boost

Answer 1

harirajanv OP

Aug ’21

To add to the above. hdd is 1tb fusion drive. disk0 is the SSD -128GB disk1 is the HDD - TB and disk2 is the synthesised disk.

when you run diskutil verifyVolume or repairVolume. at each volume level say disk1s1 or disk2s1, disk2s2 etc

No errors are reported for "Verifying allocated space"

but when you run for the container disk like. disk0s2 or disk1s2. only then the "Verifying allocated space"

it gives all those errors

warning: MT mapping (0x40000007faf09 -> 0x28aaa3, 3, C) is not completely referenced

warning: MT mapping (0x40000007fd997 -> 0xfd059b, 2, C) is not completely referenced

warning: MT mapping (0x4000000813aa7 -> 0x2d9f5a, 3, C) is not completely referenced

warning: MT mapping (0x4000000813bb2 -> 0x2da2c6, 3, C) is not completely referenced

so diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_APFS Container disk2 1000.0 GB disk0s2

/dev/disk1 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *121.3 GB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_APFS Container disk2 121.1 GB disk1s2

/dev/disk2 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +1.1 TB disk2

Physical Stores disk0s2, disk1s2

1: APFS Volume imacOSCatalinaX15 - ... 37.2 GB disk2s1

2: APFS Volume Preboot 87.5 MB disk2s2

3: APFS Volume Recovery 529.0 MB disk2s3

4: APFS Volume VM 12.9 GB disk2s4

5: APFS Volume imacOSCatalinaX15 11.2 GB disk2s5

Any one has any idea...

it is driving me crazy, which at the end is going to make me go and buy the new M1 Mac-mini or the M1-imac.

this should just be software issue, rather than hardware issue, as apple diagnostics checked and said no errors.

Thanks.`

0

Answer 2

JupiterDan117 OP

Oct ’21

I was having this same issue. After a lot of trial and error and searching online, I followed the steps on this Apple support page and it completely fixed the issues I was having with my fusion drive: https://support.apple.com/en-us/HT207584

It was super easy if you're running Mojave or later. Literally just one command in terminal!

0