File associations no longer work properly under Windows 10 after an incorrect update. Windows will not let you select some default applications. We tested several computers running the stable version of Windows 10 and all had this problem.
Update: Microsoft has confirmed this bug exists. Microsoft says it "is working on a resolution and believes that a solution will be available by the end of November 2018".
It's a strange bug. This affects some applications, but not others. For example, Windows 10 will not let you do Adobe Photoshop or Notepad ++ a default application for images or text files. However, you can set other applications, such as IrfanView, VLC or Google Chrome, by default.
For example, here's what happens when we try to set Notepad ++ as our default application for .txt files in the Windows 10 Settings application. Windows simply ignores our choice and chooses the default Notepad.
The same problem occurs when we try to choose a new file association by right-clicking on a file and using the "Open With" context menu. After selecting Notepad ++ and selecting "Always use this application", the file opens correctly in the chosen application.
However, the next time we open this file, it will open in Notepad rather than in Notepad ++. Windows simply forgets our chosen file association.
Again, we tested several Windows 10 computers running the Updated April 2018 and everyone we tested has this problem. This does not affect all applications, but at least Photoshop and Notepad ++. This bug does not seem to affect PCs running the Updated October 2018, which was shot because of several data loss bugs and has not been reissued yet. (Update: Microsoft indicates that this bug affects some computers running the October 2018 update.)
From our research and various social media posts we found, our theory is that it stopped working properly when Microsoft released the KB4462919 updated on October 9th. But we do not really know it. It is broken on the stable version of Windows 10 today and it was probably broken for a while. This certainly has the habit of working!
Windows 10 seems to have more and more problems. Why is Microsoft not testing such things before publishing updates?
Image credit: RealVector/Shutterstock.com.