If you are importing hundreds of products, a blank Product Category field in the Shopify CSV upload preview can make the whole file look broken. The preview is useful, but it is not the final source of truth for every taxonomy field. Before rewriting an 800-row file, isolate whether you have a CSV problem or a preview/display problem.
Here is the workflow I use.
1. Start from a product Shopify already understands
Create one product manually in Shopify and choose the category with Shopify's own category picker. Then export that product. Do not recreate the category text from memory and do not rely on a copied taxonomy breadcrumb from another page.
That export gives you two things that matter:
