Volume Hash Mismatch?

Guys i am just coming over here from another discussion about this problem and also encountered this problem on my 2019 macbook pro 16" laptop. Went to genius bar did all fresh installs for weeks, had same problems of fresh installs not going through until i finally got lucky with a Big Sur install finishing. A week later still the same error. I finally found a developer thread in my developers forums that was discussing the same problem and one of the guys was suggesting to not run the apple diagnostics, but the standard memtest86. It is a command line tool, but there is a OSX compiled easy GUI version, called "Rember", that you can freely download here: http://www.kelleycomputing.net/Rember/

Please run this test and i am 99% sure it will show up with a memory error. So did mine and so did a bunch of others who ran the test. Unfortunately my laptop is out of warranty, so I would have to do a motherboard swap and pay the 680 bucks for that, which makes no economical sense. But the i realized, that this is somewhat weird??? How come that all these 2019 macbooks have this problem and all apparently upon upgrading either to the beta version of Monterey (which is the issue that came up in the developer forums) or upon upgrading to the release version of Monterey (if you are a regular customer). There has to be some sort of low level firmware that has to have triggered something within our machines, since it seems to only happen upon upgrading to Monterey.

BTW, my posts have been taken down from Apple, since i apparently violate the communities User Agreement, so now the above post is listed without my theory of why this might happen, this way it might help someone and not get pulled from apple.

Hi amna2k1,

It looks like you ran into a security mechanism intended to protect you and your Mac. If you started up in macOS Recovery (gray background), I think the error was caused by a misconfigured Secure Boot policy (also known as the LocalPolicy).

Try these steps to reinstall macOS and rewrite the Secure Boot policy:

1. Shut down your MacBook Air.
2. Press and hold the power button (Touch ID) until you see the message "Loading startup options".
3. Select Options and click Continue.
4. If you're prompted for an administrator password, enter it to continue.
5. Select Install (or Reinstall) macOS, then follow the onscreen instructions to reinstall macOS.

If you run into a startup disk dialog that includes the Target Disk Mode option, go to the top of the screen and select Startup Disk -> Quit.

I recently had this problem about a month after I checked about this MAC, it recommended a software upgrade I upgraded to Monterey 12.1, which was the second upgrade? The upgrade went thru some extra steps it seemed but after that the 27" Inch Imac with solid state drive and 128 GB memory seemed to work OK for about a month. A few days ago I got the random Hash alert, and whent to applecare. They recommended shut down, wait about a minute and start up using command -R. When it booted I was advised to go to disk repair and select the drives and run the disk repair on both of the items. Then shut down and restarted. That was four days ago and I havn't noticed anything yet. The alert has not come back yet. I do not let it go into the sleep mode as the SS drive has no moving parts. I found it to be much less problematic to just shut the screen saver off, and do a restart once a week or so. The apple tech said that if the alert came back again to run the disk utily from the command R boot mode (not from desktop dock preferences), back up everything, shut off power, and then reinstall the OS again with out wiping the drive. I assume the next thing would be to totally erase the drive and reinstall from Time Machine. They said the problem could have been in th startup items on some of the solid state drives, and are working on a fix?

Here's what I ended up having to do (minus all the dead ends along the way). I backed up my drive, (in my case using Carbon Copy Cloner). I then used Internet Recovery to wipe the drive and install a clean copy of the OS.

Then I used Migration Assistant to restore my files, but when choosing what to restore I unchecked 'System & Network'.

That seems to have fixed it. Previously when I had restored everything, including System & Network, the volume hash mismatch message was there as soon as I logged in. It's been a week now and the message hasn't come back.

Did you try downgrading to the memory that came with the machine?

I did not want to believe it was a memory issue, and I did a full wipe of the drive and clean network install of MacOS only to have the error pop up on first login.

But someone else said they swapped out memory and it fixed it. So I pulled my mini apart and put it back together.

What I found was the original 8GB that came with the machine cause the VHM to go away.

And when I again swapped my 64GB of Crucial RAM back in and ran memtest86 RAM was filled with errors. (this was a lot of taking apart and putting together the mini)

memtest86 requires a 512mb USB stick formatted only to run it as boot. You also must change the boot security to allow it to boot from the stick.

There is a report above from someone who ran memtest86 and it came out clean but they continue to experience these errors.

However, it is worth looking into yourself. I RMA'd my crucial RAM, swapped in brand new 64GB and my system works fine again.

This is definitely specific to Monterey and still exists in MacOS 12.3.1. I believe it is largely a hardware issue, and has something to do with increased sensitivity to errors.

Just an update:

After a few months of reinstalling the OS and wiping and reinstalling the OS and using disk utility to repair the drive and resetting PRAM and running memtest to find no issues with my RAM...... and still getting the Volume Hash Mismatch error... I took it into the local authorized Apple repair shop (I don't have an Apple Store nearby). The guy said that Monterrey has been causing all sorts of issues with older hardware (not that I would consider my 2019 MacBook Pro to be all that old). He wiped the drive and put Big Sur back on my computer. Said that the diagnostic tests all looked good.

So I am running 11.6.5 currently. So far no issues and things seem good. After a week or so, I will check disk utility to see if there are any issues there too. Fingers crossed...

Hi amna2k1,

We understand that you're seeing an error message after installing macOS Monterey. In this case, let's try reinstalling macOS using these instructions: How to reinstall macOS - Apple Support

Take care.

jdp107, thank you very much for taking the time to complete that test. I know it was extra steps so thanks for taking that time. Hopefully it was interesting in some way.

I'm planning to write this issue up in a blog entry, and will incorporate this feedback. For me, it absolutely was corrupted memory that was detected by memtest86. It is good to know that it can appear and not be related to memory issues detectable by memtest86.

From learning this, my suggestion to people encountering the volume hash mismatch in monterey for the first time to first run memtest86. If it has failures, that's a replace it problem.

If it passes memtest86 as it did for jdp107, then the person should try the pram/nvram reset that seems to have worked (so far) for jdp107. This is part of the instructions Apple has in support for this issue.

jdp107, would you mind sharing your specific HW config and what (if any) specific event triggered the error?

FWIW, YMMV - Macbook Pro 16-inch 2019, running Monterey 12.3. Just yesterday got the "volume hash mismatch" message, with the instruction to reinstall the OS. Tried looking for answers (here and elsewhere) and discovered lots of suggestions, no solid answers. Tried reinstalling the OS via recovery (CMD-R on startup) and halfway through that process got another error message "an error occurred loading the update." Tried again, same error. Called Apple, spent time with the tech, tried Disk Utility First Aid, then tried (3rd time) to reinstall via internet recovery (OPT-CMD-R), same error message halfway through. Finally tried another suggestion to reset PRAM/NVRAM and CSM and *that* appears - for now - to have made the "volume hash mismatch" alert go away.

My takeaway from all this, as a Mac user since 1984, is a very mixed emotion. The tech is getting more and more amazing in what it can do, at the same time it's getting more and more fragile and prey to the tiniest glitches. It's not reassuring.

Update: Within a couple of hours after my previous post, the VHM error reappeared. I figured I'd done everything but a complete wipe of the SSD and a clean reinstall (via online recovery), so that was the next step. Made a Time Machine backup, did the wipe and reinstall, migrated everything back onto the fresh OS, and - knock wood - so far so good.

I may try the deeper dive of using memtest86, but right now I've already spent a ton of time on this.

Again, FWIW. So far, a week after I completely wiped the SSD, downloaded Monterey from Apple, and imported all data, apps, etc. from a backup, I've had zero "volume hash mismatch" error messages. I am cautiously optimistic that the clean reinstall has done the trick.

(NOTE: I also changed the APFS partition(s) of the drive. Before, I had created 3 volumes, for different storage reasons. I had, unwittingly, also created the 3 as fixed partitions as opposed to flexible APFS volumes. Force of habit from the old days. When I wiped the SSD clean, I created only one APFS volume. Everything on the other two previous volumes was simply data, and I figured I could as easily put all that into folders on the one volume, instead of having 3 separate volumes. I have no idea if that had any effect on the volume hash errors.)

I also just got a copy of MemTest 86 and have been running it. So far, 2 passes and zero errors. I will let it go overnight to do justice to the advice everyone gives about "how many passes" - again, I am cautiously optimistic it will give me no errors.

I reinstalled from the recovery partition about a week ago. So far so good.

Hello amna2k1,

Thanks for following up.

We recommend restarting you Mac and trying to reinstall one more time. If you get the same message and the start up disk does not appear, then you'd want to reach out to Apple Support for further assistance.

Get Support

All the best!

I had the same problem on a Late 2015 iMac, that unfortunately has had problems anyway. But, the new OS IMHO triggered this new issue. I dunno. Maybe it found an underlying issue that has been lurking. I had done a full wipe of the HD when this problem first arrived with 12.1. Then brought in data from TimeMachine. Issue surfaced again.

Yesterday, I downloaded 12.1 from the Apple App. Store, and just did an OS re-install. I've only had about an hour in front of the iMac, and so far no re-surfacing of this issue.

Seems like I'm not the only one that had this problem, so I don't know if I can blame my oldie but goodie iMac.

When did the problem first appear?

Was there a crash prior to seeing the error or did it seem to start showing out of the blue?

My guess is you need to replace the RAM on the machine.

You can find out for sure by making a memtest86 USB boot drive, and running the test. I had a ton of errors, replaced the ram and it fixed it.

Please run memtest86 and report results.