Just to make sure everyone is aware.... Several people have upgraded to Windows 10 and found they are no longer able to play Vanilla or Warlords Civ4. Deckhand has uncovered this link which explains the problem in detail. However the crux of it is that people have found that Windows 10 is unable to read many copy-protected dvd's to verify they are genuine. This screws up Civ4 vanilla and Warlords, which use copy-protected discs (as well as a lot of other old games). BtS is not affected because it runs without checking that you have an original dvd in the drive. I haven't heard anything about Steam, but I'm guessing Steam users might not be affected by this problem if your Civ is downloaded from Steam and doesn't rely on a dvd. This is not a problem that's within our ability to fix. So it looks like, until either Microsoft fix the problem, or someone comes up with a workaround, Windows 10 users will be unable to play vanilla or Warlords GOTMs (or for that matter, any vanilla or Warlords Civ games - with the possible exception of Steam users). So the message obviously is - if you want to continue playing all GOTMs, you'll need to avoid upgrading to Windows 10. Or keep at least one computer that's running an earlier version of Windows.