Solved I'm trying to associate a file type with a Microsoft Store app.

The app isn't in the default apps list so in Folder Options I had enabled Show hidden files and now I see, but can't access WindowsApps. When I click it says I don't have permission and when you click continue then it says I have been denied permission and to gain access I will need to use the security tab. I had gone to
Properties > Security tab > Advanced button And am now stuck here:

You would help us greatly by telling us the file type and the app you are referring to.

App: Microsoft Photos
File types: J2C, J2K, JBG, JNG, JP2

Photos doesn't have native support for those image formats. It won't open them, even if you forced the file type associations.
You need to use another app which understands them.

I'm downloading the Universe FILE Viewer from the Microsoft Store now.

LAPIII said:

App: Microsoft Photos
File types: J2C, J2K, JBG, JNG, JP2

Click to expand...

You can use NCH Software's Pixillion program to convert these file types into the more popular types that most software can read.

It's free software.

bob