Issues with File Hash Failures on Windows 11 Over SMB Share

So, on my side, SMB Multichannel is enabled and SMB signing is off for both machines and the storage. This was a fresh install last week, so all Windows updates have been applied. The files that were hashed locally or from the network would sometimes be fine, but then fail an hour later. The way these video files work is that their hashes are stored in an XML file, and during validation, a new hash is generated to match the original. What’s peculiar is that smaller files like XMLs and audio hash correctly, but the large video files consistently fail. Plus, I've had multiple validations return different wrong hash signatures each time. Has anyone pinpointed this to just one machine? Can you replicate the issues when copying files on the same drive?

I've seen some reports that the latest Windows Updates could interfere with SMB shares. It might be worth checking if any recent updates coincide with your issues.

That's definitely strange! Those SMB features shouldn't alter the actual file contents. Have you tried copying one of the video files to a different location on the same drive? You mentioned issues only arise when copying to an external share or a different local drive, but what happens on the same drive? Also, it’s odd that you're seeing different hashes on the same files later. Are these changing hashes visible from other computers accessing the share? That might give some insight into where the problem lies.

I had a similar experience on a couple of my Windows 11 machines, and it was super frustrating. It turned out that Windows 11 was being 'helpful' with SMB. Once I disabled SMB signing and multichannel on the Win11 system, the hashes stopped fluctuating. The connection to the same server from Windows 10 was fine all along, which pointed to an issue with the client stack rather than the NAS. I also recommend checking your NIC drivers and temporarily disabling any real-time antivirus on both ends as a test. It seems like an outdated driver mixed with Windows 11 and SMB signing/multichannel can be a tricky combo, especially for large files.