Overview

Sellers encounter Error 90045 when Amazon’s bulk‑upload system cannot read a file because it is saved in the wrong format. The issue typically appears during inventory, pricing, or listing updates that rely on spreadsheet templates. Correctly formatting the file as a tab‑delimited text document eliminates the error and keeps large‑scale uploads on schedule.

Key Points

• Root cause — The upload engine rejects files that are stored as native spreadsheet types (e.g., .xlsx, .csv) because it expects a plain‑text, tab‑delimited layout.
• Typical mistake — A seller edits a downloaded template in Excel, clicks “Save,” and leaves the file in .xlsx format; Amazon then returns Error 90045 during the upload step.
• Straightforward remedy — Re‑save the completed file using the “Save As” option and select the “Text (Tab delimited) (*.txt)” format (or .tsv from Google Sheets) before attempting another upload.
• Template freshness — Downloading the latest template from Seller Central each time prevents hidden changes that could corrupt the file structure.
• Verification tip — Opening the saved .txt file in a basic editor such as Notepad should reveal data separated by visible tab spaces, confirming the correct format.
• Team alignment — Anyone who prepares bulk files—virtual assistants, inventory managers, or third‑party agencies—must follow the same saving protocol to avoid repeated re‑uploads.

How Error 90045 Happens

1. Template download — A seller pulls the current inventory or listing flat file from Seller Central; the file arrives as a .txt tab‑delimited template.
2. Data entry — The file is opened in a spreadsheet program (Excel, Google Sheets, LibreOffice). The seller fills rows with SKUs, quantities, or price changes.
3. Default save — Pressing “Save” keeps the document in the program’s default format (e.g., .xlsx). When the file is later submitted, Amazon’s parser cannot interpret the binary spreadsheet structure, triggering Error 90045.