error: mismatch between extentref entry reference count

I'm using Ventura 13.2.1 and whenever I run DiskUtil after using TimeMachine for a while, I see bunch of local snapshots and usually many of them are corrupted:

Checking snapshot 1 of 1 (com.apple.TimeMachine.2023-02-16-145125.local)

warning: mismatch between extentref entry reference count (2) and calculated fsroot entry reference count (1) for extent (37861578 + 1)

It results in the whole disk being corrupted according to Disk Util.

There are two possible "solutions":

reformat the SDD and re-install everything. The problem will appear again anyway one the local snapshots are created
delete the snapshots but the problem will appear again

I can reproduce it on two machines - Mini M1 2020, MacBook Pro 16" 2019

System report shows the SSD as healthy

Is there a way to fix it? I don't see it as healthy behavior :(

MacBook Pro 16″, macOS 13.2

Posted on Feb 16, 2023 06:44 AM

Top-ranking reply

ApMaX

Level 2

159 points

Posted on Apr 1, 2023 01:21 PM

I could fix a similar error in macOS 13.3 (22E252) Ventura running First Aid NOT on the volume, but on the container on top (just below the disk). Actually, First Aid suggested that in the text mixed with other text (which may cause people not seeing it!) because otherwise it said that it could not check if there was enough space. Amazing!

First Aid is an awesome piece of engineering, but its interface could be improved. Errors should show in red color, suggestions in blue and good news in green. And never say that it was successful when there are problems and the green top check mark is not shown. Otherwise it could be utterly misleading.

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error: mismatch between extentref entry reference count

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