OK... how would this happen is my question. It is literally just setting a registry value. When its selective, there is usually some flag or value that was not required before now being required that would cause it to fail. So... what did they change?
I just checked on two of my machines running Windows 10 Pro 1803.
One machine had no problems with associations. The .txt extension was properly associated with Notepad++ (as it had been for a long time). I could even set the default for .txt to Notepad and back to Notepad++ with no problems.
On the other machine I had never set associations for Notepad++, so .txt was still set to Notepad. Here I did encounter the problem described in the article. In Windows Settings, Notepad++ was not even available as an assignable option. If I right-clicked a .txt file, I could chose to open it with Notepad++, but the association would not stick.
Here's what I did to fix the problem. I ran Notepad++ as admin, went to Settings -> Preferences -> File Association and moved .txt (and some others) over to the Registered Extensions column. After closing Notepad++ I could set the association properly and have it stick.
This appears to be a registration issue. Note that this is different from association as the former is what tells Windows that the program is capable of handling the filetype (I could be wrong about this). It's possible that KB4462919 caused some registrations to be reset (as the article speculates), but this is not a new phenomenon. I've had this issue occasionally going all the way back to the XP days. However, I've generally had no problems with associations if the program had correctly registered its filetypes during installation.
Thanks, this will be helpful when my parents and grandparents start calling in 3..2..1..
This is an intended feature to prevent browser and app hijacking . the registry will detect changes to default apps and switch them back if not changed in the correct way . I have been deploying default apps to all my 20 + sites without issue. Windows 10 changed the way you deploy default apps from group policy to the use of default appassociation.xml
My personal copy of Windows 10 Pro decided that it is no longer valid as the key stored on the Microsoft servers is only good for Windows 10 Home. I even ran the Windows troubleshooter where it listed all of the valid Windows 10 Professional licenses stored on my Microsoft account, but still told me that I only own a Windows Home license. It then pointed me to the Windows Store to purchase a new license after revoking my old license by placing the Windows Activation watermark on my desktop. After researching this annoying message the entire night, I discovered lots of other valid Windows license owners with the same issue. It seems that Microsoft knows about the issue and a fix is coming. At least my data didn't disappear into thin air. That would suck if it did it twice.