I have found a workaround for Windows 7, but unfortunately I can't help with Windows 10! Perhaps a similar approach might work, however!
I looked through the list of updates for Windows 7 in the last month and uninstalled a couple that I suspected could be responsible. I have uninstalled the following two updates, which got rid of the problem: KB3207752 (security update) KB3210131 (some generic update)
I uninstalled KB3210131 first, which didn't help, and then I uninstalled KB3207752, which fixed the problem, so it's either the security update or both updates. I did not reinstall KB3210131 to confirm. Obviously, uninstalling security updates is not a good fix for a problem! I have no idea what's actually in these updates, so someone with more Windows knowledge might have more insight. I'm hoping that January's security updates won't cause an issue, so we can continue happily using rbbox.