Problem in network Windows 11 24h2

Not sure, whether this explains it for all of your issues,

but I had at least a similar issue in the sense that Windows 11 lost the (wired) network connection and claimed that no Ethernet Cable was connected.

Indeed the port on the ethernet switch was not active, so I plugged the cable to the neighboring port - and it worked - for a while.

I then realized in my "managed" ethernet switch, that the Windows 11 PC was actually blocked due to a "Denial-of-Service" caused by "SMAC=DMAC" (send and receive MAC are the same).

This never happened with the same PC running on the same port, while it was still using Windows 10.

I disabled the monitoring for the port --> no issues since more than a week - let's keep the fingers crossed.

>> The solution of setting a static IP does not work in most cases, as it does not work in mine.

Please read other replies in this thread, and try each of the suggestions.

This is the real issue that MS techs are not talking about !!!

Following the Windows 11 24H2 update, users are frequently reporting issues accessing network drives or experiencing LAN manager problems, often due to stricter security settings that now enforce SMB signing by default, potentially blocking connections to older devices or network shares that don't support this feature; this can manifest as inability to access network drives, connection timeouts, or error messages related to SMB authentication.  Key points about LAN manager issues with Windows 11 24H2:

• Stricter SMB security: The update has tightened security by enabling SMB signing by default, which can cause problems with older devices or network shares that don't support this feature.
• Guest access restrictions: The update may also restrict guest access on network shares, further impacting connectivity.

Potential solutions:

• Check network settings: Verify your network settings including IP address, subnet mask, and DNS servers on both the client and server.
• Adjust SMB settings:
  • Enable guest access: Depending on your network environment, you may need to enable "Allow insecure guest logons" in the Local Group Policy Editor to allow older devices to access network shares.
• Disable SMB signing: If absolutely necessary, consider temporarily disabling SMB signing on your network, but be aware this can compromise security.

Following the Windows 11 24H2 update, users are frequently reporting issues accessing network drives or experiencing LAN manager problems, often due to stricter security settings that now enforce SMB signing by default, potentially blocking connections to older devices or network shares that don't support this feature; this can manifest as inability to access network drives, connection timeouts, or error messages related to SMB authentication.  Key points about LAN manager issues with Windows 11 24H2:

• Stricter SMB security: The update has tightened security by enabling SMB signing by default, which can cause problems with older devices or network shares that don't support this feature.
• Guest access restrictions: The update may also restrict guest access on network shares, further impacting connectivity.

Potential solutions:

• Check network settings: Verify your network settings including IP address, subnet mask, and DNS servers on both the client and server.
• Adjust SMB settings:
  • Enable guest access: Depending on your network environment, you may need to enable "Allow insecure guest logons" in the Local Group Policy Editor to allow older devices to access network shares.
• Disable SMB signing: If absolutely necessary, consider temporarily disabling SMB signing on your network, but be aware this can compromise security.

Following the Windows 11 24H2 update, users are frequently reporting issues accessing network drives or experiencing LAN manager problems, often due to stricter security settings that now enforce SMB signing by default, potentially blocking connections to older devices or network shares that don't support this feature; this can manifest as inability to access network drives, connection timeouts, or error messages related to SMB authentication.  Key points about LAN manager issues with Windows 11 24H2:

• Stricter SMB security: The update has tightened security by enabling SMB signing by default, which can cause problems with older devices or network shares that don't support this feature.
• Guest access restrictions: The update may also restrict guest access on network shares, further impacting connectivity.

Potential solutions:

• Check network settings: Verify your network settings including IP address, subnet mask, and DNS servers on both the client and server.
• Adjust SMB settings:
  • Enable guest access: Depending on your network environment, you may need to enable "Allow insecure guest logons" in the Local Group Policy Editor to allow older devices to access network shares.
• Disable SMB signing: If absolutely necessary, consider temporarily disabling SMB signing on your network, but be aware this can compromise security.