Hash Mismatch after Ventura install, still there and Apple techs online haven't heard about it

FYI, Many of the "Volume Hash Mismatch" threads on these forums seem to have involved bad memory. There is a good chance your Mac has a hardware issue.

You can try running the Apple Diagnostics to see if any hardware issues are detected.

Creating & booting from a Memtest86 USB stick can perform a longer more thorough memory test as well. I have found changing the Memtest86 CPU options to "Sequential" or "Round Robin" have resulted in more cases of detecting hardware issues. Most of the times the test did not result in any errors, but the computer froze during the tests which is just as significant at identifying a problem (I ran the tests without problem on another identical Mac without any freezes).

You can also run EtreCheck and post the report here using the "Additional Text" icon which looks like a piece of paper. Many times the summary logs at the end of the report have shown memory related issues.

To be fair to the Apple techs, the "Volume Hash Mismatch" errors have only recently been starting to be reported on these forums so it is not surprising that techs are not aware of any "known" issue.

Would suggest using the advise from @HWTech and run the " MemTest 86 " as instructed.

This may give a more clear insight if Memory Modules are at play.

Below are users experiencing the Memory Mismatch issue and in there cases a Bad Memory Module was the cause .

Please help - Terminal.app keeps crashing upon reopening - macoS Monterey version 12.4

Volume hash mismatch, cannot reinstall MacOS

Monterey rev 12.4 - Hash mismatch

Volume Hash mismatch

Strange Disk Space Issue

Well, it’s not clear yet what actually causes the hash mismatch error in macOS, as users have reported it randomly appearing, or after a significant system crash or kernel panic. However, whenever user experience this error message, it’s a good idea to immediately backup all data on the Mac with Time Machine or any other backup method of choice.

Further, you can also try the below troubleshooting methods to fix the issue:

1. Reset SMC

2. Reset PRAM/NVRAM

3. Reinstall macOS

Hope this will help!

Do you have any 3rd party memory modules installed? If so what brand are they and were did you get them?

I was ok for a few days, no longer getting the Hash Mis Match error - BUT - now my Nov 20 Mac Book Pro is randomly shutting down 'due to error'. Log report is not helpful. I have sent the report to Apple, not sure if that is even successful. I see I am not the only one in this cycle, Bsperl.

FWIW, this is a user forum. No one here can answer questions about what the techs know or don't know.

Thx. I ran full diagnostics and had the same result as Bsperl 10-27-22- ref code ADP000 and no issues found.

I rebooted a few times and so far all is well. I'll wait to see if this reappears.

Hash Mismatch showed up a few times. I backed up everthing, scanned and cleaned. It continued randomly. I installed Ventura, 2 weeks ago. It just showed up again. No issues installing Ventura.