Organizer: Many files are not getting imported, but why?
I’ve been using the Elements Organizer (PSE 18, Windows 10) for over a year now, but I’ve never figured out the right way to proceed, and I only recently recognized how big a problem I have. The way I work with my photos is to first download them into a subfolder. I browse them, delete the ones I don’t want, and then edit the photos I do want. My camera is a Lumix, so the main folder is named Lumix, and each subfolder is named with the date and place I took my photos. When I’m done editing all the items in the folder, I move the edited JPEGs files into a permanent folder, which is where I should be able to view them with the Organizer. I archive the original JPG and RW4 files by moving the work subfolder to a 1 TB drive.
For the majority of my files, this seems to work: when I open the Organizer, it imports them from the permanent folder, which is a subfolder of a Watched folder. But not all files are imported. A few it doesn’t import because it says they’re already cataloged (but it doesn’t identify them, so I’m not sure if that’s a—or THE—problem or not). Worse, for many files in that folder it shows no warning, it just doesn’t import. I may have hundreds of files (I'm not sure) that the Organizer hasn’t imported. If I search within the Organizer by Filename, it finds those files, Information identifies the correct location, and it can display the file, but it still doesn’t show up when I select that folder from the Organizer file list. And selecting Import Media with the folder doesn’t bring them in either. They also don’t show up when I search for All Untagged Items. And if I apply a tag to that file, it doesn’t show up when I select that tag. How can that be?
I’m completely mystified. Can anybody shed some light on what is (or might be) going on, and how I can fix it? And is there a way for me to identify all the missing files, besides opening one folder at a time in Windows File Explorer and comparing it to what the Organizer shows?

