For testing purposes I always have a VirtualBox machine with the latest Windows 10 build. I installed Windows 10 build 10041 and faced an issue that the VirtualBox video driver did not work in it. So I couldn't get mouse integration, auto-resize option for the guest display, clipboard sharing and so on. Thankfully, it is very easy to fix this issue.
As you might have noticed, the latest versions of Oracle VirtualBox come with Windows 10 support. The appropriate template is available in Windows and Linux versions of the VirtualBox software:

However, after you install VirtualBox Guest Additions, the video driver does not work. That's because this Windows 10 machine template has video acceleration disabled, so the driver can't be installed and the virtual video device cannot be recognized.
You just need to change it.
1.
Turn off your Windows 10 VM.
2. Open its
settings and go to the Display section on the left. There you need to
tick both checkboxes in "
Extended features:"

3. Click
OK and
turn on your VM.
It will install and activate the proper driver automatically.

You will get all missing features. You are done.
source:winaero