I have all the plugins installed, and NEF is in the list of of files when I load default extensions. NEF is not in the drop down list of file extensions. Windows 10 absolutely will set an association between NEF and Irfanview. I can set the association to Paint Shop Pro with no problem, but I cannot change it to Irfanview. I even deleted all the associations to NEF in the registry and still Irfanview won't associate. What's the problem?