After upgrading Windows 10 (Fall Creators Update) invoking Virtualbox' guest additions gives a file system error in Windows. I have app-emulation/virtualbox, app-emulation/virtualbox-additions, app-emulation/virtualbox-modules of version 5.1.30 and app-emulation/virtualbox-extpack-oracle version 5.1.30.118389 installed here. It had been working before the "Fall Creators Update". I'm running Gentoo-sources 4.13.7 here.