Conclusion:
After a remote session with Tony, we tried different things like removing all visual c++ versions, close all background apps, remove overlays and chatting programs, but nothing changed. In the end it seems to be the Bitdefender 2017 that cannot handle the DB client renaming the executables after launch, and so the client launches, but then gets closed. Added the daemonbuddy folder to exceptions list, and then tested for about 6 hours. Everything works fine now.
My question still remains, why does it work without any issues the first time after a fresh install, because a new executable is created then also, and after the client gets closed, it will not work again.
Perhaps I will never find out.
Thread can be closed as this is a good enough solution for me. Hope others will find it useful as well.
Thanks