Keep an original copy
Begin by exporting the relevant product, variant, or collection metafields and saving an untouched copy. Work on a duplicate so you can compare the final file with the original.
Keep identifying columns intact. Choose a matching method that uniquely identifies your rows, such as a variant ID or a consistent SKU. Be careful when spreadsheet software reformats identifiers, numbers, or dates.
Treat the preview as part of the work
After uploading, check the column mapping and validate the file. A preview should tell you how many values will be created, changed, deleted, or rejected. Read individual before-and-after values as well as the totals.
Pay attention to the meaning of blank cells. Skipping a blank and deleting an existing value are different actions. Metafield definitions also matter: a date, number, reference, and text value each need the right format. Resolve errors before applying.
Keep the undo file and verify the result
Retain the undo file before the first write. Keep the Shopify admin tab open while the import runs, and use the app’s resume workflow if the operation is interrupted.
Read the completion report, including skipped or failed rows. Open a few representative records in Shopify to confirm the stored values. If those metafields appear in your storefront, check the displayed result there too. Importing a metafield does not automatically add a theme block that displays it.