Thanks for the reply Tom982 .
I've started a topic at VirtualBox forums - https://forums.virtualbox.org/viewtopic.php?f=6&t=49948
- and user called mpack
have suggested to look on how my system handles uncertified drivers.
I am trying to manually install one of virtualbox drivers (of course doing it NOT in safe mode) and it gives me an error as per picture I've attached there in VB forum.
The reason I need to use my virtualbox in safe mode is that I need to install Guest Additions for 3D option. It has to be installed while running VB in safe mode.
I've got Optitex software with 3D models which I cannot see as my virtualbox currently do not support 3D.
Hope you can give me some advice on this issue as it looks that no one else can.