block checksum mismatch

[vulcancoins]

Hello,

I also started getting "block checksum mismatch" errors about a week-and-a-half ago. (today is 13 november 2025)
Restarting bitcoin-qt seems to alleviate the problem ... for a while.

Until it errors out again, always on chainstate/1284467.ldb
Deleting this file causes a resync, which seems to work ...

Until a few hours later ... debug.log shows:
Fatal LevelDB error: Corruption: block checksum mismatch: I:\bitcoin\chainstate/1284467.ldb

I am using bitcoin-core 30.0 on win11 25H2.
The blockchain is located on an (internal) 1Tb nvme sdd, ntfs 4k blocks. (WDC WDS100T2B0C-00PXH0)

s.m.a.r.t. claims my ssd is healthy.
I cleaned the ssd (using diskpart clean) and tested it by copying an 800gb file of random data file to the sdd and comparing it with the original.
No errors ...

I ran memtest86, no errors.

I keep a copy of the blockchain on a nas.
When the error occurred the chainstate on the nas was about two weeks old, 1284467.ldb did not yet exist.

I copied the backup to the sdd and launched bitcoin-qt again.
After synchronizing, some hours later the error reoccurred on the same file: 1284467.ldb

I am not using any virusscanner, and the built-in one I set to ignore the \bitcoin\* folder and bitcoin-qt.exe.
(And even if it was that, the file would/should be deleted/quarantined, not modified.)

I am at the end of my "troubleshooting-fu", hence my post here, hoping someone can shed some light as to what the underlying problem might be.

Apart from a complete resync, which might take weeks, I don't know what else to try.

Thanks in advance, for any pointers or clues.

PS This behaviour started shortly after the win11 update to 25H2, so I am assuming I'm not alone?

[vulcancoins]

Update:

 I have run bitcoin-qt directly from the nas.

And the exact same error occurs:
Fatal LevelDB error: Corruption: block checksum mismatch: z:\bitcoin\chainstate/1284467.ldb

Which leads me to think it is not a hardware problem.

[vulcancoins]

I have deleted everything in \chainstate
I have deleted everything in \blocks\index
I have deleted from \blocks all .rev files, and all blocks after blk05216.dat.

 bitcoin-qt claimed resynching was necessary, only 10 hours to  ...

[nc50lc]

I have deleted everything in \chainstate
I have deleted everything in \blocks\index
I have deleted from \blocks all .rev files, and all blocks after blk05216.dat.

 bitcoin-qt claimed resynching was necessary, only 10 hours to  ...

This is because you did unnecessary steps.
You already identified the issue which is just a corrupted file in your UTXO set.

All you had to do is start Bitcoin Core with --reindex-chainstate command line arg and it'll rebuild it from your existing block files.
But if your node is in prune mode, it'll have to redo IBD anyways.

PS This behaviour started shortly after the win11 update to 25H2, so I am assuming I'm not alone?

It's hard to associate this with Windows update.
It's usually caused by sudden shutdown or anything that can corrupt the data while it's being written to disk / already written to disk.
But that's also a possibility if it's caused any of the above.