Originally Posted by theducks
The plugin author will probably have an answer later.
I suspect this is an error/damage in the collections database kept on/and used by, your K3.
Do you see any odd
characters in a collection name on your K3?
That's true! Collections disappeared from my K3. I don't cared much (the book is way too engaging) and don't know when happened. Maybe when tried to use this plugin?
Now I recreated one collection and apparently everything is OK now.