Windows 10 Cumulative April 2021 Update causing all client workstation to not able to access the server.

DocBoyLLC 1 Reputation point
2021-04-14T22:38:13.707+00:00

Clients running Win 10, Server is running Win 2012. On my client workstations today I installed Win 10 April 2021 update (2021-04 Cumulative Update for Windows 10 Version 2004 for x64-based Systems (KB5001330)). After installing the update, the client workstation can no longer connect to the server. I get the Network Error message "Windows cannot access \Server; Check the spelling of the name. Otherwise, there might be a problem with the network. To try to identify and resolve the network problems, click Diagnose" (Clients still have internet access, Windows network icon on bottom right of screen shows it is still connected properly to the network).

Error code: 0x80070035
Network path was not found

I tried "troubleshooting." Win 10 claims there is issue with DNS Server.

Under Network Icon --> The client can visibly see other workstations, printers, and the server. Clients can access other workstation clients. When clicking on the server icon, the workstation cannot access the server directory.

I tried various regedits on the client workstations, no avail. Huge problem for me as I'm running a patient database that is stored on the server, and the client workstations constantly access the server and the patient database.

After I uninstalled the April 2021 update, everything is working ok again, and the clients can access server contents again.

Anyone run into this issue? Please help.

Microsoft System Center
Microsoft System Center
A suite of Microsoft systems management products that offer solutions for managing datacenter resources, private clouds, and client devices.
824 questions
0 comments

2 answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. Robinson, Gray 1 Reputation point
    2021-04-15T19:02:42.523+00:00

    You're not alone. It appears MS may have used this update to disable SMB1, which will cripple communication for a lot of Windows-based software programs.
    Changing software data paths to use the server's IPv4 address has a positive impact (e.g. "\ServerName\Share\DataDir" becomes "\ServerIP\Share\DataDir").

    Edit:
    I've been told that re-enabling Multicast Name Resolution in group policy (gpedit.msc) can also reverse this issue without rolling the update back.

    0 comments
  2. DocBoyLLC 1 Reputation point
    2021-04-19T16:35:19.557+00:00

    @Robinson, Gray

    I went into the Local group policy editor, and set "Turn off multicast name resolution" to "Disabled" (this setting was previously set to "Enabled"). Flushed the DNS and rebooted the workstation, and still did not work.

    Any other suggestions?

    I am not able to change the software data path. The software I use will only recognize "ServerName" Even though it "sees" the "ServerName" I cannot change the software to recognize the server's IP address instead of its name.