Overview

Amazon returns error 90004 when a bulk feed contains bytes that do not conform to the platform’s UTF‑8 requirements. The message pinpoints the exact line and character where the illegal byte appears, allowing sellers to locate and correct the problem quickly. Ignoring the error stops inventory, pricing, or listing updates from being applied, which can delay sales for high‑volume sellers.

Key Points

• Error pattern — The notification reads “In line {X}, character {Y} contains invalid byte(s) {Z},” for example “In line 23, character 12 contains invalid byte(s) 0xE2.”
• Primary cause — Bytes that fall outside the accepted UTF‑8 range, such as curly quotes or hidden control characters, trigger the rejection.
• Typical sources — Copy‑pasting from Microsoft Word, exporting from Google Sheets, or importing supplier catalogs often inject non‑UTF‑8 symbols.
• Immediate fix — Open the file in a plain‑text editor, navigate to the reported line 23, character 12, delete or replace the offending symbol, then save the file as UTF‑8 without BOM.
• Impact scope — A single invalid character can invalidate an entire feed of thousands of SKUs, causing all updates in that batch to be ignored.
• Prevention tip — Always generate feeds from Amazon’s downloadable templates, which are pre‑configured for the correct encoding.

How Error 90004 Occurs

1. File upload — The seller selects a flat file, XML, or tab‑delimited feed and clicks “Upload.” Amazon’s intake service stores the file temporarily for validation.
2. Encoding scan — Amazon’s parser reads each byte, checking that it follows UTF‑8 rules; for instance, a line containing “Café ™” includes the trademark symbol (0xE2 0x84 0xA2) that may be mis‑encoded.
3. Invalid byte detection — When the parser meets a byte sequence that cannot be decoded—such as a stray 0xC3 without a following continuation byte—it records the line and character position and aborts further processing.
4. — Amazon returns error 90004 with the precise location, preventing any data from being written to the catalog until the file is corrected.