SMB sharing not working after windows 10 update Build 2004 update

Win10 20H2 fixes the issue.

Previously when 2004 broke smb1, I rolled back.

There was no registry change or any other modification made to the system.  After Win10 20H2 upgrade was installed via Windows Updates;  SMB1 worked as it did before the upgrade.

Thank you Microsoft.

I am not sure it is a solution:

I preserve my primary PC from 2004 upgrade and 2 weeks ago system force the upgrade to  20H2. After that problems with SMBv1 appears - sometimes all mapings works well, but some hours after system start File Explorer opening cause endless ''This Computer' refresh with unfinished progress bar. In this case command 'net use' hangs. The only solution is system reboot, but this is unacceptable.

kB

BIG, FINALLY WORKED OUT

Thanks for your comments.. I will look over what you sent..

Appreciate the information

We had similar problems also with Win 10 20H2 and Server 2019

We fixed it with this article:

https://docs.microsoft.com/en-us/troubleshoot/windows-server/networking/guest-access-in-smb2-is-disabled-by-default

Guest access in SMB2 disabled by default in Windows

Configured registry value:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters] "AllowInsecureGuestAuth"=dword:1

PS: we also enabled smb1