Virtualbox will not have support for windows 10 until windows 10 is officially released. But because it has the ability to be installed on windows xp-8.1 and Linux, it has partial compatibility to be used in windows 10 but like most programs it does not have solid stability yet. I use linux as my main OS but I also use windows from time to time, I tried installing a few programs including Oracle on windows 10 and it simply would not work. You could try disabling the network driver which causes hang ups in most cases, but that is about it.
Although Some versions of VMWARE will work, I have tested about 4 or 5 different versions but it seems like VMware is the only one that works for the preview.