Volume Hash Mismatch?

That’s a bummer.

Since you have run memtest86 and you’ve done the complete system format and OS install it must be a hardware failure outside of memory.

Possibly the logic board has got some thing wrong with it. Have you done any customizations to this laptop or is it a stock factory device?

Other than reverting to Big Sur which seems to be less sensitive to hardware problems, you may need a new computer.

I got the Hash Mismatch warning twice since I bought the last manufactured 27" IMAC In October 2020. Specs: 3.8GHz 8 core 17, added memory 128 GB 2133 MHZ DDR4, AMD Radeon Pro 5500 XT 8GB, and 2TB Apple solid state drive. (Cost Over $5000) Started out with BIG SUR then upgraded to the latest Latest Monterey OS. I don't think I started getting the Hash mismatch BS using Big Sur? I got the first mismatch alert about three months after adding xtra memory. It said to reinstall OS. I have Applecare so called tech to find out, they seemed basically baffled. The first solution they suggested (after all the basic normal stuff like resetting the PRAM, restarting , slowdown, etc, you know the routine) running disk first aid, they suggested running disk first aid from the Command R startup., it seemed be trouble free for a few weeks ater that and I had the following issues, Preview, Photos, and Mail all crashed or froze several times, the screen froze, over night crashes, mouse wouldnt work and, plenty of minor glitches and errors and crash reports saying I had a problem. Reported all crash reports in detail. Kept up with OS upgrades (reinstalled twice) and got the Hash Mismatch alert once again about a month ago. Upgraded and reinstalled OS again, and noticed some speed and overall performance improvements but still had some of the annoying problems, but so far, despite all the annoying problems, I have been able to recover and do restarts, shutdown, etc, and was able to continue to normal functioning with annoying glitches mentioned above still happening about every 4-5 days. Called applecare again and asked the tech for suggestions. They really didn't have much of an answer other than that I was covered and they would fix the problem if the unit totally fails. I've been a MAC user and semi techno nerd for over 20 years (and took programing the in the 1970s) and none of the seven desktops I have had since were problem free, I've had almost every problem imagineable and even ending up talking to senior software develop team members for solutions, so I was hoping this one might be better, didn't happen! At this point I have pretty much resolved (from previous nightmares) that as long as I have three external backups, Carbonite, and cloud backups that at least if I have a catastrophic failure I can save my stuff, and get a newer model someday and suspect Apple will never come up with a fix. After reading all the discussions posted about Hash mismatch, it seems that it appears that there may be so many technical issues with all the different models concerning this problem there may never be a solution or magic fix that prevents it from happening. I think most of us MAC users have some sort of loyalty and use them for various positive reasons but its sort of sad that this type of thing is rampant in any manufactured electrical or mechanical device that use chips and processors. Considering the technical aspects of computers its absolutely amazing that they even work at all. I was told by someone who was a senior official with Apple that with problems like the HashMstach that if they don't get enough complaints (and especially customer feedback) they will basically ignore the problem. Good luck.

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.

One more FWIW - 2+ weeks after my last status report, things are still running without the mismatch error showing up. So I'm again of the mind that erasing the drive and doing a clean install of the OS has "fixed" the issue.

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...

jdp: Thanks for the update. Sorry to hear this continued to be a problem for you. I agree, 2019 isn’t exactly “older” yet. Both my macs are 2018.

I think perhaps five years is starting to get in the older side of things. But this is mostly because of the massive hardware capability increases Apple Silicon has been delivering on Mac and before that on iOS devices.

IIRC, you have a 2019 MBP, is that right.

Would you please post the full hardware spec so there’s a record here?

Also, if I have that right, the 2019 MBP does support user upgradeable memory. Would you please confirm if you’re using the RAM that came with the system, or if you’re using an upgrade which brand / config?

Even if it passed memtest, it would be good to know this stuff.

Finally, would you mind marking your calendar to come back in 30-45 days to report on stability under Big Sur?

Just to update:

Currently running Big Sur 11.6.5

MacBook Pro (16-inch, 2019)

2.3 GHz 8-Core Intel Core i9

16 GB 2667 MHz DDR4

Intel UHD Graphics 630 1536 MB

It does not have user-upgradeable memory, so everything is as it came from Apple.

It has been 2 weeks since reverting back to Big Sur. Overall it seems fine. No Volume Hash Mismatch warnings. Disk Utility is clean. I think Safari may have crashed once a week ago or so but nothing really beyond that.

Fingers crossed it keeps up.

What do I do with this?

I’m seeing this too on my 2019 MacBook Pro. Never had a problem with this computer until Monterey.

I had this happen too. It took me two tries and a very long time - most of a day - to install Monterey, and now I have to reinstall it?? Urghhhh.....

Having same issue. Initially had trouble installing 12.0.1, and now getting this hash error. I'm on a 2019 MacBook Pro.

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

I have an iMac from 2016 with Monterey 12.01 and got the message „hash mismatch on volume…“

How can I fix it?

Thanks

The only fix I found that helps is to run “Sudo Purge” from the terminal but it’s only temporary the hash mismatch may present itself again

Volume Hash Mismatch. Hash mismatch detected on volume disk1s5. macOS should be reinstalled on this volume.

What does this mean?