Windows 11 update 24H2 changes network access

Updated today, I have a few shares that allow guest access, so that wasn't working, I had to enable guest access on Windows which seems is now disabled:

Set-SmbClientConfiguration -EnableInsecureGuestLogons $true

After that those shares started to work again.

Thank you MS.

FOUND THE ANSWER!!! (at least for Win11 Home 24H2) File sharing is now working!!

The Microsoft tech discussion is here: https://techcommunity.microsoft.com/t5/storage-at-microsoft/smb-signing-required-by-default-in-windows-insider/bc-p/4285348#M1851

Need to turn off RequireSecuritySignature in the 24H2 client.

To see the current SMB signing settings, run the following PowerShell commands:

Get-SmbServerConfiguration | FL requiresecuritysignature

Get-SmbClientConfiguration | FL requiresecuritysignature

To disable the SMB signing requirement in client (outbound to other devices) connections, run the following PowerShell command as an elevated administrator:

Set-SmbClientConfiguration -RequireSecuritySignature $false

To disable the SMB signing requirement in server (inbound to your Windows 11 Canary Insider Enterprise, Pro, or Education edition device), run the following PowerShell command as an elevated administrator:

Set-SmbServerConfiguration -RequireSecuritySignature $false

To access PowerShell as Admin, Press Win + R keys together to open Run.

Type PowerShell in Run and press Ctrl + Shift + Enter keys together to open the PowerShell prompt with administrative privileges.

What is the exact 24H2 Build # you are using?

Here is the problem that I saw with Build 26100.2152 and reported by other users:

After updating to 26100.2152, I found that "File and printer sharing" got turned off, and I had to turn it back on to get my local network to work properly again.

I also had to enable the new option in the security settings "File and printer sharing (Restrictive)"

Enabling the above setting got rid of the yellow warning message showing on 1st shot.

This security setting "File and Printer Sharing (Restrictive)" was disabled in one machine after the update to 26100.2152.

I had to enable manually "File and Printer Sharing (Restrictive)", in my case just for Private network which is what I 'm set for.

After that the file sharing started to work correctly.

When it failed before changing the settings, it was just hanging trying to access the 26100.2152 PC and eventually pop up the message below.

It worked fine after fixing the settings described above.

What's new in Windows 11, version 24H2 for IT pros | Microsoft Learn

SMB firewall rule changes

The Windows Firewall default behavior has changed. Previously, creating an SMB share automatically configured the firewall to enable the rules in the File and Printer Sharing group for the given firewall profiles. Now, Windows automatically configures the new File and Printer Sharing (Restrictive) group, which no longer contains inbound NetBIOS ports 137-139.

This change enforces a higher degree of default of network security and brings SMB firewall rules closer to the Windows Server File Server role behavior, which only opens the minimum ports needed to connect and manage sharing. Administrators can still configure the File and Printer Sharing group if necessary as well as modify this new firewall group, these are just default behaviors.

For more information about this change, see https://aka.ms/SMBfirewall. For more information about SMB network security, see Secure SMB Traffic in Windows Server.

I tried everything, and I think I finally found the culprit. In Windows Defender Firewall with Advanced Security, 24H2 does two things: (A) disables all File and Printer Sharing rules, and (B) adds a bunch of rules called File and Printer Sharing (Restrictive) [blah blah blah].

In some cases, even if (A) is not done, (B) is done and something else is disabled that breaks file sharing.

The solution is:

1. Go to Windows Defender Firewall with Advanced Security => Inbound Rules
2. Scroll down to File and Printer Sharing. Look at column "Profile" and make sure all rules with your correct Profile are enabled (right click - enable)
3. Enable all items at the bottom which have the word (Restrictive) in the name. The most important one is called File and Printer Sharing (Restrictive) (SMB-In).

To be clear, just enabling File and Printer Sharing (Restrictive) (SMB-In) should do it, but I went overboard to make sure the computer responds to pings, etc.

Thanks for this Andrew - but afraid it didn't work for me and my 24H2 PC. I have tried all the suggestions I can find, including yours, but nothing seems to work. My Netgear router USB attachment (Readyshare) doesn't show under Networks, nor do any computers on the home network. Interestingly, the only thing that does show up is a Synology NAS. However, the problem 24H2 computer shows up fine on my other 23H2 computers on the network. Please post if you come up with any other suggestions!

YES ABSOLUTELY TRUE... SOMETHING BROKE SPENT 8 HOURS TODAY TRYING TO FIX IT. STILL BROKEN. THANKS A LOT MICROSOFT.