virtualbox.org

I'm running a couple Windows 10 Insider Preview versions in Vbox v5.0.12. It seems everytime a new build gets pushed out the Network adapter breaks and I have no network connectivity. I am thinking it would be helpful to have Guest Additions installed, apparently this would allow me to map shares on the host which might help me fix the adapter issue. I also gather that Guest Additions is supported on Windows 10 build 10240 but of course, Preview versions are higher and I expect that's part of the issue. Regardless, reading the Help doc on installing Guest Additions, it says, "In the "Devices" menu in the virtual machine's menu bar, VirtualBox has a handy menu item named "Insert Guest Additions CD image...". My problem here is I don't see any such menu bar in the virtual machine. What am I missing?

The GAs have nothing to do with networking - GA shared folders do not use the network. You'll finding that GA installation is conveniently described in the user manual.

The menu bar is at the top of the VM window, including the View submenu. It must be visible except either (a) in fullscreen mode - which you can't be using if the GAs are not installed, or (b) if you purposely disabled it using the "setextradata noMenuBar" command. If you did the latter then the user manual tells you how to undo it (section 9.20.1).