Well, just having posted the bug, will allow for other people, perhaps Windows 10 users, to test.
I think I misunderstood before. This problem happens with SVG files which were not made with Inkscape, except for Inkscape files saved as Plain SVG? That would seem to imply there is something found in Inkscape SVG, which is missing in the others. But I don't have the technical info to know what part of Windows is looking for that info. So the bug report is definitely the right call.
Moini, what is that huge list of members on the right side of bug report pages, under "May be Notified" ? "May be notified" gives me the idea that might be the bug management team. However, I'm always seeing very spammish names there (such as, at the moment, quickbook payroll something, or the alphabet names like fdsasdfdsa). So it's puzzling what that list is about.
Oh, I'm totally with you, about Windows 10. When my Windows 7 Home computer just became old and wasn't functioning correctly, and it was time for an upgrade, I went with Windows 10. I had heard that 10 is going to be the last Windows os to be fully contained on the users system. After 10, all Windows os will be cloud-based.
So I already had made the decision to move to Linux. But it was the update system, which was one of the many reasons I could not tolerate Windows 10. All I can think about 10, is "what was MS thinking?". Let's shut down the system, without the user's knowledge or permission, with no warning (well, I got 10 seconds to stop it, before the system shut down....and that happened while I was on the phone with tech support, and I didn't see it in time) for sometimes hours at a time, while it goes to get updates on its own. As if having no control over when updates happen is not bad enough, there's also no way to choose which updates you want or need. And there were 5 or 6 other stupid things I couldn't live with.
Anyway, I returned that computer, and bought a Windows 7 Pro (Home not available anymore). (I don't know why, but it never has received the offered Windows 10 upgrade icon in the system tray - thankfully!) And....well, if nothing else goes wrong in my life (when it rains it pours, you know), in the next few weeks I'll probably start testing Linux systems, and choosing which one I want to install. And hopefully, by the time this computer dies, I'll be mostly on my own with Linux only.