Hello! When opening links to HTML5 videos, I can watch them as they load but as soon as the video is fully buffered/downloaded, it either dissapears or shows a "unloaded image placeholder"-icon, depening on source. This issue doesn't seem to happen on sites such as Youtube - I've only ever seen it on sites hosting gif-esque HTML5 videos, such as the following: http://i.imgur.com/u9oX1hD.gifv . Whenever this playback issue happens, a message from Mozilla shows on the top of the page, reading "To improve video quality, you may need to install Microsoft's Media Feature Pack", and a link to this page: https://support.mozilla.org/en-US/kb/fix-video-audio-problems-firefox-windows?as=u&utm_source=inproduct . This all started to happen after the Anniversary update. My version of Windows 10 is an N-version, meaning the media features of the default windows are not preinstalled. The issue is that I HAVE installed the Media Feature Pack already, and if I try to download the latest and install again it says that it's already up-to-date. I can't seem to find any other threads about this particular issue. I can provide further details I have not been clear enough about my issue, or if there's any kinds of test you'd like me to do. Thanks, Towkin