Re: Windows 10 Default App/Program Problem
As crazyman143 mentioned, I would try clicking Start > Settings > System > Default apps tab
Under Photo viewer, change that to "Windows Photo Viewer"
If that doesn't work;
I'm guessing you've tried the Windows "Refresh" option?
Humans are the only creatures that won't live up to the their potential. Give everything your all. When you die, die on E.
So I ask you, what do you intend to do now?