I have been trying to chat with support on this issue, but I can never get through.
I have a video purchased on my desktop under 8.1 xbox video via my MS account, "The Interview".
Shortly after purchasing it, I upgraded to Windows 10 via the insider preview, and kept updating to almost every build until the final.
during the course of the preview, MS made the switch from Xbox video app to Movies & TV app, the movie continued to work throughout the preview builds.
However once the final of Win 10 was made available, I wiped my desktop, to clean install Windows 10 Pro (upgrade from 8.1 Pro) from scratch. same MS account, and the video is not accessible on my desktop at all.
I have tried the "restore my available video purchases" option in settings, and nothing.
I check in the Windows Store, when I search for the movie, its listed as owned on the search page, I click on it to bring up the page, it lists it as available to buy, I click that, but then tells me that I will be charged for it, so I cancel, as I already own it.
The movie is however listed on my Windows Phone 8.1 (Samsung) using the same MS account, and is playable.
Just not on the desktop I purchased it from.