Why is my network messed up after update to windows 11 24H2

It's clear from the many posts in this thread that there are 2 possible problems being caused by Windows 11 update 24H2.

1. Network attached drives and computers are no longer visible in Windows file Explorer.
2. Windows errors when attempting to map network attached drives.

My own problem relates to that stated under Problem 1. Despite trying every suggested setting in this thread and other various posts on the Internet, nothing has helped to restore my ability to browse my NAS drives directly using Windows Explorer and SMB. Nothing, that is, other than rolling back to Windows 11 23H2!! It would be most helpful if someone from Microsoft joined this discussion and confirmed that they are aware of both of these problems and are working towards a proper solution.

Had this happen to me this weekend. I too had tried turning on and off all services and everything else Microsoft suggested,

Until I found this link.

I followed the instructions on the site and now the problem is fixed.

Make sure you have all passwords requirements off on advance network sharing.

Also make sure you do this to all windows 11 computers with update, Hope it helps.

FIX: Windows 11 24H2 Cannot Access Network Shares (0x80070035). - WinTips.org

How old is your NAS?

Does it support SMB3/2, or only SMB1?

I had to change some settings in my Synology as well, to allow server signing

you could install SMB 1 under windows features even if this is not recommended

Admittedly my Conceptronic Ch3HNAS NAS drives are fairly long in the tooth now but I have always been able to browse their content using Windows file Explorer, up to and including windows 11 Pro Version 23/H2. I can also confirm that SMB 1 and 2 are ticked under Windows Additional Features. Therefore, having tried all the various "fixes" detailed in this and other threads, I can only conclude that update 24/H2 has introduced a, so far, unacknowledged anomaly. I am left to wonder why there has been so little input from Microsoft to this official Microsoft Community thread?

Apologies. You are correct.

Meanwhile I could solve the issue with my Synology NAS and Win11 24H2.

I had to chenge in group policies under Computer Configuration- Windows Settings- Local Policies- Security Options the setting

Network security: Restrict NTLM outgoing  :allow all

After that, access to shared folder was as before in 23H2, I even didn't need to allow the insecure guest login to see my NAS in the network neighbourhood.

This worked for 3 PCs AMD and Intel installing 24H2.

Surpisingly it worked without changing anything on a fourth PC which I upgraded on Friday to 24H2, maybe ther was a recent update of 24H2 which solved the issue?