Can not change old default Windows Program Viewer to new "Photos"

For a friend trying to help is the opposite of most posts trying to get rid of Photos (the Win 10 new recommended to change to another.

In my friends case in settings default in both sections to change defaults - either for pictures or for .jpg files the option box to change program opens and lists 4 including "photos" but can not change the default to any from old Windows Picture Viewer. Can't change to paint either. will not allow change FROM Windows Picture Viewer to newer Photo.

I suspect registry entry issue but from other posts, it is usually the opposite, need register change away FROM Photos but in my case trying to get TO new Photos. Haven't found exactly what registry entry to look for.

Certainly not necessary to fiddle with the Registry.
Control Panel > Default Programs > Set your default programs.
Scroll down to the Windows Photo/Picture Viewer, Select and Choose defaults for this program.
Untick everything and Save.

Select and Choose Photos and tick appropriately in there, and Save.
Restart Windows.

The other route is Settings > Default apps > Set defaults by app

Helmut said:

Control Panel > Default Programs > Set your default programs.
Scroll down to the Windows Photo/Picture Viewer, Select and Choose defaults for this program.
Untick everything and Save.
Select and Choose Photos and tick appropriately in there, and Save.
Restart Windows.The other route is Settings > Default apps > Set defaults by app

That is what we did on both of those routes. But after you click to choose Photos and closes the drop down it still shows Windows Photo Viewer. Likewise if try and change to say paint same thing. on my computers works just as you say but somehow not on his which makes no sense. We both have latest Win 10 updates and in fact my laptop is basically the same as his .

CountMike said:

https://www.tenforums.com/tutorials/...-a.html?filter[1]=Programs%20Features

We are trying to do the opposite, get rid of Photo Viewer.

Photo Viewer seems irratic. For example opened one jpg but not a 2nd. I had him e-mail me both jpg files and I can open them fine on 3 different programs so not corrupted. But his Photo Viewer seems to open some jpg's but not others. The default for all photos and jpg files (two routes to set defaults) shows Photo Viewer. With his problem with Photo Viewer trying to get changed to new Photos but can not change the default from Photo Viewer- very strange.

I wonder if in order to change the default he needs to be logged in as admin like when go the other way. I just thought of that from reading other thread and will have him try.

I will work with him further. Need to go to bed, 4AM here :)