I hear you Windows 10 users! You're using Windows 10 and everything is just hunky dory. Well Merry Christmas because this morning
Windows 10 forced update KB 3135173 changes browser and other defaults
The cumulative update not only knocks out PCs' default settings, it prevents users from resetting them
Yes, if Chrome was your default browser guess what? It's now Edge. Using Adobe PDF Viewer as your default? No you're not. Edge has edged it out. Use Photoshop Express, Google's Picassa or Google Photos as your default image viewer? Foolish mortal you now use the Windows cell phone Photo App! Video, music, any media that Microsloth has an app for you now use those apps as your default.
No, it gets better.
YOU CAN'T CHANGE THEM BACK! Yup, try it. "An app caused a problem!" You'll learn to hate that error message. One user anticipated the problem and saved a .reg file with registration settings for his chosen default applications. Smart man. But outsmarted by Microsoft. When he restored the .reg file the associations were not restored.
The culprit is
Cumulative Update for Windows 10 Version 1511 for x64-based Systems KB3135173. But it doesn't matter. As a loyal Windows 10 user you have no right to refuse to download and install the update. Then you have the right to wait to see if Microsoft is serious here or will actually fix the situation. You are at their mercy......or lack of it.
Why do I recommend shields up against automatic updating of computers from Windows 7 to Windows 10? Microsoft just bolstered my case big time! Windows 10 isn't free and it isn't an operating system. It's malware, spyware, adware. It's a trojan of the first degree. And it isn't free.
Windows 7 users, we're at MS-DEFCON 2, all patches are suspect. Do not install until they are better analyzed. There is nothing urgent in there that you need to have anyway so waiting won't hurt.