There are some Knowledgebase articles that pertain to all customers, regardless of which Blackbaud product(s) they use (except for K-12 ON Products and MicroEdge products, FIMS and GIFTS). These articles have the "Not applicable" product. 

This ensures that you don’t inadvertently exclude helpful information from search results by filtering on a product. 

To exclude these articles from displaying in your search results, hover your cursor to the right of the Not applicable product filter and click the circle with the line through it.

To learn more about filtering KB search results, review How does the Knowledgebase search engine work? How do I search KB?