Is there any way to search for comics that don't have metadata. I know it is not normal, but I have comics in different folders that I would like to add metadata without having to enter each folder... with a simple search it would save me a lot of time.

I also tried to search like number:" " or title: (empty) but I don't know the characters for empty text or number.

Thanks a lot!

No, there is no such an option. This should be something done automatically by YACReaderLibrary, once you hace a series identified new issues should get metadata automatically…but until I get something better for dealing with metadata you don’t have much options.