Sharing resources on local private network

They are many weeks I've been struggling with sharing issue on my network and as it is said "a picture is worth a thousand words" so here what is happening and what I don't understand.

Does someone have a clue ?

Of course, files & folders sharing is set, all on the same workgroup, network discovery ON, network is of private mode with DHCP and the issue occurs whatever AV & firewall are ON or OFF.

The odd thing is that if I can't ping desktop from laptop by IP, it works in netbios but in both cases I just can't connect a desktop shared folder from laptop, using IP or netbios name.

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I'm always using the same crendentials on both my devices in my local network, same user name, same password.

Addendum : this windows 10 set up is a fresh one without any OS tempering. All that was done was OS & software installations.

Just for testing purposes, I've booted to an old windows 7 partition. No issue at all, connecting a desktop shared folder from laptop was like a breeze.

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A new step on the way of understanding what's happening.

Desktop device has a shared folder, so it should be displayed in explorer in the network section.
It is, BUT... Trying to access it by double clic gives me "Network error, windows is unable to access the resource....".

Any idea ? To be through, I don't use sharing wizard, I've never did since Xp, I use advanced settings.



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I've narrowed it down ; the culprit is... Portmaster.

I've installed it to really block network access for some applications obviously bypassing defender firewall. It is so diligent that it blocks everything to simple sharing.

Next step : find the right setting.