XnView Software

I haven't been using XnViewMP for a while because it would not sort photos by Categories. To my chagrin, I still cannot seem to find a way to do this in XnViewMP... I hope I'm mistaken and shall be grateful if someone will tell me that this is today very well possible!

Select a jpg picture, and in "Categories" pane, let a mark in a checkbox for a category ..

Go to "Categories Filter" pane, can you see a category having (1) item ? if yes, select this line and the browser will display the categorized picture.
If you want to save this mark into picture embedded keywords, go to settings metadata, and mark "export DB category to ..." and other settings you choose.

To modify categories, you must first select a picture, then you can work in Categories pane (create, rename etc ..)

Is your installation folder locked or protected by system (Windows ?) ?
if yes, go to settings, integration, paths and choose a non-locked place ...

Thank you, Michel08, for pointing me to the Categories Filter. I don't know why I didn't see this before, but it makes sense now. Again, I very much appreciate your help here.