When I build a product system that includes input flows with flow names that exist in my flows list as products of other processes, but that have categories and subcategories assigned, OpenLCA does not find and connect them. If I eliminate the category and subcategory from these product flows, they get connected when I build a product system. There does not seem to be a good way to search and automatically connect to flows with categories and subcategories.
Do you mean eleminating the category and sub-category in EcoSpold data sets?
openLCA flows are not identified by names but by an internal UUID. In EcoSpold data sets the category and sub-category belong to the identity of an entity (note that there are no UUIDs in EcoSpold 01 data sets). So openLCA will generate two different UUIDs for flows with the same name but different categories (this is very important for elementary flows).
Please see http://www.openlca.org/documentation/index.php/UUIDs_for_EcoSpold_01_data_sets how openLCA generates UUIDs for EcoSpold 01 data sets.