Why does my Amazon flat file upload get rejected or overwrite listings incorrectly?

One common cause is duplicate ASIN or SKU rows in the flat file. Amazon processes rows sequentially, so a duplicate row with stale data overwrites the correct row uploaded earlier in the same file. Removing duplicates before upload prevents this.

How do I deduplicate an Amazon inventory export by ASIN before re-uploading?

Upload the export to Deliteful, enter 'asin' as the key column, and download the clean file. Each ASIN will appear only once per worksheet.

Can I deduplicate a flat file workbook that has one sheet per product category?

Yes — each sheet is deduplicated independently in a single upload. Specify the same key column name (e.g., 'seller-sku') and the tool applies it to each sheet that contains that column.

Does Deliteful support the .xlsx format that Amazon Seller Central uses for flat files?

Yes. Both .xlsx and .xls formats are supported. Download your flat file from Seller Central, deduplicate it in Deliteful, and re-upload without format conversion.

Deduplicate Amazon Flat File Uploads and Inventory Exports by ASIN or SKU

Amazon flat file catalog uploads and inventory exports frequently contain duplicate ASINs or SKUs — from merged spreadsheets, copy-paste errors, or combined exports across multiple storefronts. A duplicate row in a flat file upload causes Amazon to reject the file or silently overwrite listing data with stale values. Deliteful removes duplicate rows by ASIN, SKU, or any key column before you upload.

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Amazon sellers managing large catalogs across multiple brands or storefronts often build flat files by combining exports from Seller Central, a 3PL, and a product information management system. Each source can produce overlapping rows for the same ASIN — especially when updating price or inventory across a shared catalog. A single duplicated ASIN row in a flat file upload can overwrite a correct price with a stale one, suppress a listing, or trigger an Amazon error code that delays the entire batch.

Deliteful deduplicates every worksheet in your Excel workbook in one upload. Enter 'asin' or 'seller-sku' as your key column and the tool keeps the first occurrence of each unique value per sheet, dropping all subsequent duplicates. For workbooks with one sheet per brand or category, each sheet is cleaned independently. Output is a values-only Excel file — formatted correctly for re-upload to Seller Central after your edits.

How it works

1
Export your flat file or inventory report from Seller Central
Download your catalog or inventory Excel file from Amazon Seller Central or your inventory management tool.
2
Upload to Deliteful
Upload the .xlsx or .xls file — multi-sheet workbooks are handled in one step.
3
Enter your key column
Type 'asin', 'seller-sku', or whatever column uniquely identifies each listing row.
4
Download and upload to Amazon
Receive a deduplicated flat file ready to upload to Seller Central without duplicate-row errors.

Frequently asked questions

Why does my Amazon flat file upload get rejected or overwrite listings incorrectly?: One common cause is duplicate ASIN or SKU rows in the flat file. Amazon processes rows sequentially, so a duplicate row with stale data overwrites the correct row uploaded earlier in the same file. Removing duplicates before upload prevents this.
How do I deduplicate an Amazon inventory export by ASIN before re-uploading?: Upload the export to Deliteful, enter 'asin' as the key column, and download the clean file. Each ASIN will appear only once per worksheet.
Can I deduplicate a flat file workbook that has one sheet per product category?: Yes — each sheet is deduplicated independently in a single upload. Specify the same key column name (e.g., 'seller-sku') and the tool applies it to each sheet that contains that column.
Does Deliteful support the .xlsx format that Amazon Seller Central uses for flat files?: Yes. Both .xlsx and .xls formats are supported. Download your flat file from Seller Central, deduplicate it in Deliteful, and re-upload without format conversion.

Create your free Deliteful account with Google and deduplicate your Amazon flat files before your next catalog upload — no card required.