Network shares unaccessible, or network not visible anymore, a lot of netowkring problems

[AndrejPirman]

Hi,


in past month I've had dozen of issues reported from different clients, all related to networking malfunction, mostly after some Windows updates. The symptoms are:

• One client reports that majority of Windows PCs in their LAN simply do not see servers and network shares anymore. Hovever, if they manually type UNC path \\SERVER\Share into Windows Explorer, they CAN reach the share. But 100+ people were used to simply browse the network and navigate to desired share that way. Now most of PCs do not see ANY computer on network anymore.
• Another client reports, that approximatelly half of computers do not have access permissions to network shares anymore. When they navigate to network share, they get error, something like this:
  \\share is not accessible. You might not have permissions to use the network resource....
  The problem is, that they are not asked for permissions anymore, like it was in the past. Those are variety of PCs, some Win7, mostly Win10 Pro, some updated to latest 2004, but most of them on 1909 or lower. Server was NOT updated, at least not manually.
• Another client cannot access RDP connections anymore from some 30% of their PCs. They have a bunch of RDP connections from one PC to another due to the nature of their business, but all RDPs are within LAN. Now all of the sudden some PCs simply throw RDP error, like:
  Remote desktop cannot connect to remote computer for one of these reasons....
  I would understand if this was ONE PC. But no, involved are so many computers, different branch, different OS versions, I simply cannot find any pattern.
• Then a lot of clients report, that their network scanner simply does not want to scan to SMB anymore. Newer scanners, using SMBv2 or v3, but simply no go.

Is it full moon or what?

I suspect Microsoft disabled some networking features silently in background, maybe some minor updates in the background, which had major consequences. Anybody knows of something like this in past month or two?

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