Is there a permanent fix for the SMB file sharing issues caused by the latest windows 11 updates?

I have two identical SKU laptops purchased from the same vendor/system integrator within a few days of one another and found that both machine's Security Identifiers, SID, were identical. After an upgrade to Win11 24H2 they failed to share SMB files with each other producing the exact same errors here: https://support.microsoft.com/en-us/topic/kerberos-and-ntlm-authentication-failures-due-to-duplicate-sids-76f7394d-c460-4882-9ed1-d27e0960f949

Both these machines had full share access to other machines on the network - just not each other.

None of the proposed registry or group policy remediations for SMB breakage worked for me. Some people are reporting that SIDCHG can be used to reset the machine's SIDs on an existing installation.

MS provides a work-around for business customers but as an individual I'm completely SOL unless I want to run sysprep or SIDCHG and risk bricking a machine. The vendor created this problem: MS made it a bigger problem.

Hi, There

As I known, this issue’s been popping up since recent Windows 11 updates (especially KB5065426). They’ve tightened network and SMB security, which often breaks simple file/folder sharing.

Before uninstalling the update, try these fixes first:

• Switch network to Private – Settings > Network > Properties > set to Private.
• Turn on sharing – Settings > Network & Internet > Advanced sharing >enable Network discovery and File & printer sharing.
• Recheck permissions – Right-click the shared folder > Properties > Sharing > make sure the right users (or “Everyone”) are added.
  • Firewall – Allow “File and Printer Sharing” through Windows Defender Firewall for Private networks.
  • Guest access fix – If your shares don’t require login, enable insecure guest logons:
• Group Policy: Computer Config > Admin Templates > Network > Lanman Workstation > Enable insecure guest logons.
• Or Registry: HKLM\SOFTWARE\Policies\Microsoft\Windows\LanmanWorkstation → AllowInsecureGuestAuth=1
• Duplicate SID issue – If the PCs are cloned, create a new local user or re-sysprep; it fixes SID conflicts blocking shares.
• SMB signing – Run PowerShell:

Set-SmbServerConfiguration -RequireSecuritySignature $false -Force

If all else fails, uninstall the update for now and wait for Microsoft to patch it.

I know I am not alone as this is a widespread Windows 11 bug where a Windows Update corrupts the core SMB components, and then subsequent updates cheerfully re-break what I just fixed.

TL;DR: Windows Update broke SMB. Go to Settings → System → Recovery → “Fix problems using Windows Update” to force a repair install. Then pause updates before they can break it again.

After wasting days on tweaks, sfc /scannow, DISM, registry hacks, service resets, NewSID workaround, I found the only solution that actually sticks, and it comes from Microsoft itself. Ironically, it’s also delivered via Windows Update.

The Nuclear Option That Works

Around 2022 or later, Microsoft has quietly added a “Repair Install” button that forces Windows to replace itself with a clean copy, while keeping your files, apps, and most settings intact.

1. Go to Start → Settings → System → Recovery. (Wait, be noted that it is not the same "recovery" that came from control panel, perhaps that's why we ignored it easily...)
2. Under Recovery options, click “Fix problems using Windows Update” (or “Reinstall Windows while keeping your files and apps”).

Follow the prompts. It will download a clean system image (≈30 mins) and reinstall Windows (≈20 mins) with a couple of reboots.

Why this works: It replaces the corrupted SMB drivers (mrxsmb.sys, srv.sys) and service configurations that sfc and DISM often miss.

How to Prevent It From Happening Again

Since we now know the culprit is a rogue update, it is wise to do these immediately after the repair:

1. Create a System Restore Point right now (sysdm.cpl → System Protection → Create). Name it “Post-SMB-Repair” or "Recovery-from-SMB-Hell".
2. Pause Updates for at least 2-4 weeks (Settings → Windows Update → Pause updates).

If the problem dares return, you’ll know exactly which update is to blame. Use the Show/Hide Updates Tool to block that specific offender indefinitely.

It’s a special kind of poetic justice that the fix for a Windows Update breakage is… another Windows Update. The left hand breaks, the right hand offers a bandage, but only if you know where to look.

This method finally gave me a stable SMB stack after months of frustration. Hope it helps you reclaim your network shares without having to perform ritualistic sacrifices.