sorry I had not seen your answer.
To be honest I have turned to a paying tool, Parallels Desktop, that I had extensively used in the early 00's (when I switched to Mac) and that was working really well (I had been a paying customer for years), but I didn't need anymore for several years now and had not installed it in my new Mac.
So given the problems I now have with VB I decided to give a try (trial period) : I'm absolutely impressed by the integration level in macOS, the easiness and fluidity of installation and use, it downloads the OS and installs it automatically, with proper keyboards, sharing folders and files (secured) between host and VM, all automatic... and it's stable.
I just tried with a linux install : same, even faster.
I have always been very supportive with VB since the very beginning, but I must confess that for the moment I don't have much options left.
I hope a solution will come up so I can go back "in the free world"
![Smile :)](./images/smilies/icon_smile.gif)
PD : and thanks a lot for the help and suggestions of those who came here into that thread to try to help me
![Smile :)](./images/smilies/icon_smile.gif)