I recently had a windows update on my desktop, since then videos on netflix and twitter (and a few other sites) will no longer play. Whenever visiting twitter I get a bar pop up at the top suggesting I install "Microsoft's Media Feature Pack" and links me through to this article - https://support.mozilla.org/en-US/kb/fix-video-audio-problems-firefox-windows , I have the pack installed and it's up to date, I've tired via the Add Features system in Windows and via direct download, both to no avail. Twitter will not load or play videos and netflix is the same. On Netflix I'm getting: "Oops, something went wrong... Unexpected Error" and error code F7355 (see this article which indicates browser trouble https://help.netflix.com/en/node/105186). Here are some other things I've tried, none of which have worked: * Checking for updates on windows * Checking for firefox updates * Checking for updates with the DRM addon Widevine * Ensuring Widevine is "Always Active" * Starting firefox in "Safe Mode" * Using a private browsing tab I am running: * Windows 10 Pro N (as said above, I have installed the media pack in several ways) OS Build: 18362.295. * Firefox Developer 70.0b3 64 bit. I've also been seeing similar issues on my fiances machine with standard Firefox but her's says that Widevine has crashed on the top bar rather than suggesting we install Window's Media Feature Pack, although the other symptoms are the same. I don't have her machine to hand to grab versions from there but everything is up to date at time of writing and I've tried the same troubleshooting techniques on that machine as well. Really stumped on this one and I'm very reluctant to switch back to Chrome simple to play netflix videos, but likewise it's quite important I can play videos around the web. I'll try anything else to fix it at this point, all suggestions welcome!