With the latest release of Windows 10 build 9879, Microsoft has slowly started to update the install experience with the new platform by changing the background color but it's still a bit buggy.



From Neowin:

Last week Microsoft pushed out the last Windows 10 build for the year that bumps the build number up to 9879. For those of you who have not installed the build - and we don't blame you if you haven't, as these builds are not for production use - the installer has changed slightly.

As you can see in the screenshot above, the background is now white, whereas it used to be purple and in later screens (below), you can see the older color boxed in to the gray background. These are some of the first changes that Microsoft is making to the install experience and we fully expect more updates as we get closer to the release of Windows 10.

  Microsoft begins to slowly update the install experience with Windows 10