Shopify product imports are strict because one CSV can create products, variants, prices, inventory settings, images, SEO fields, and product status all at once. A spreadsheet that looks normal in Excel can still fail if the first row does not use Shopify's exact column names, if the file is saved in the wrong encoding, or if the same product handle appears where Shopify expects a unique product.
The most important columns are structural. Handle identifies the product and usually becomes the product URL slug. Title names the product on the first product row. Option1 Name and Option1 Value describe variants such as Size or Color. Fields like Variant Price, Variant SKU, Image Src, and Status must also use Shopify-friendly formats.
The safest way to debug an import failure is to separate structure problems from data problems. First check the header row. Then check encoding. Then sort by Handle and review product groups. Finally inspect variant rows and required fields. That is the same order EcomCSVFix follows when it repairs a file.