If I am not mistaken, Windows is the only OS, that uses local time for the system clock (instead of UTC). This means that in multiple boot configurations, every restart of the system into Windows will screw up the system time. In order to reset it (in Ubuntu 16.04), use
sudo timedatectl set-timezone Etc/UTC
Transferring files from the host to the guest OS and vice-versa doesn't work out-of-the-box when you install VirtualBox from the Ubuntu repositories and download an Ubuntu VirtualBox image (e.g. from http://www.osboxes.org/virtualbox-images). After installing the guest additions, drag-and-drop didn't seem to work for me and I needed to set up a "Shared Folder". After setting it up via the GUI, it doesn't automatically appear on the guest desktop. You need to mount it:
Ripping DVDs is a thing of the past, but occasionally I still need to do it. However, it happens so rarely that evertime I have either a new computer or a new Linux distribution and I need to install the necessary software. This time I am on Ubuntu 16.04. I usually use Handbrake and it is very comfortable, but handbrake sometimes fails to do the job. This time, I had to resort to MakeMKV. However MakeMKV only rips the video to an MKV container but it does not compress it.