hm. do we really need to run samba to be able to join to a windows domain or mount a samba drive? Probably hosts should join to AD too. But I have no idea about the real scenario. I mean (I don't know really but) is this a real domain, do we have a real workgroup here, where is it managed? Is there an AD somewhere here?

If the OP wants to access files from other computers on the linux PC then samba does not need to run. The file browser can browse the network for windows shares. If wanting to access files from the linux PC on the Windows PC then samba is required.

One thing to note with net bios naming is that all workgroup/computer names should be unique and less then 16 characters. Some distributions default hostname is localhost which does not work as a network netbios name.

I assume this is a home network and therefore no AD/domain.

How is that possible. Once we change workgroup name on Windows/OSX PC's we have full network access between all PC's
on the network. Windows/OSX both ways on Linux only Windows share from Linux!
Doesn't matter if it is either. Even with workgroup name HOME full access to all PC's on the network. Except of course the Linux PC
We had this network since XP times so I think we now how to set up Windows filesharing.

To get filesharing working from Linux we only had to change one parameter on our Windows/OSX machines.
To adjust Linux to accept our usual workgroup name seems to be a hazzle.

linux does not accept anything, but it looks like you cannot reach your workgroup from linux, so windows does not accept the request from linux side. Either wrong credentials or incorrect setup.
I don't know how did you setup your windows network at all. Now if samba is not running editing smb.conf (=change the workgroup) probably meaningless (if I remember well).
Again you need to try where you need to replace <servername> and type in the name of your windows server (one of them, you can try several...). Optionally you can also add -d3 (that will give a lot of info).

Linux does accept everything as long as workgroup is named WORKGROUP. Any other name is not accepted,

As I am new to Linux I concequently tried a number of distros. The one I am trying to use is KALI
However also tried BackBox and Mint. Both these distros have no problem networking with windows on non
default workgroup names.
Copied smb.conf from BackBox and put it on the Kali install and rebooted. Still no connection to
HOME workgroup. This tells me it must be some other settings then those found in smb.conf

If I understand you correctly, you can view the Windows shares from Linux, but not the other way around?

Ah, new information. Kali Linux is not suitable for new users IMO. It is aimed at experienced users for advanced Penetration Testing and Security Auditing. The problem could be due to the firewall configuration.

Haven't tried to set up Windows to Linux yet. Was trying to get it to work one way initially.
Isn't BackBox a similar distro. I think I read somewhere that Kali was based on BackBox
As far as I know there is no firewall in Kali unless you install one

please read this link about kali: https://www.linuxquestions.org/quest...ad-4175614092/
And again, linux does not accept anything, but windows. You need to configure linux (samba?) to be able to connect to windows shares. Looks like some defaults occasionally works. And again: you want to share something on windows, the rules are set on windows (this is called server side), linux here is just a client which should be configured according to the rules set on your server(s).
Using different linux distributions (with their defaults) is not the best way to configure samba client, you need to set up the proper credentials which will be accepted by windows. Since you modified the setup, default settings will not work any more.