xtekky/gpt4free · error · UnsupportedFormatException

Could not convert stream to Markdown. No converter attempted

Error message

Could not convert stream to Markdown. No converter attempted a conversion, suggesting that the filetype is simply not supported.

What it means

Thrown by MarkItDown's MarkItDown.convert() (vendored in g4f/integration/markitdown) as UnsupportedFormatException when it iterates every registered converter and none accepts the input stream — no converter even attempted conversion. It distinguishes this from FileConversionException (raised when converters tried and failed): here the file type is simply unrecognized.

Source

Thrown at g4f/integration/markitdown/__init__.py:125

                if res is not None:
                    if isinstance(res.text_content, str):
                        # Normalize the content
                        res.text_content = "\n".join(
                            [
                                line.rstrip()
                                for line in re.split(r"\r?\n", res.text_content)
                            ]
                        )
                        res.text_content = re.sub(r"\n{3,}", "\n\n", res.text_content)
                    return res

        # If we got this far without success, report any exceptions
        if len(failed_attempts) > 0:
            raise FileConversionException(attempts=failed_attempts)

        # Nothing can handle it!
        raise UnsupportedFormatException(
            f"Could not convert stream to Markdown. No converter attempted a conversion, suggesting that the filetype is simply not supported."
        )

    def convert_stream(
        self,
        stream: BinaryIO,
        *,
        stream_info: Optional[StreamInfo] = None,
        file_extension: Optional[str] = None,  # Deprecated -- use stream_info
        url: Optional[str] = None,  # Deprecated -- use stream_info
        **kwargs: Any,
    ) -> DocumentConverterResult:
        guesses: List[StreamInfo] = []

        # Do we have anything on which to base a guess?
        base_guess = None
        if stream_info is not None or file_extension is not None or url is not None:
            # Start with a non-Null base guess

View on GitHub (pinned to 973504e177)

Solutions

1. Confirm the file type with `file yourinput` and that its extension matches the content.
2. Install the optional converters for the format (e.g. pip install 'markitdown[all]' or the specific extra like pdf/docx) so a converter exists to accept it.
3. If the format is genuinely unsupported, convert it externally first (libreoffice --headless --convert-to docx, pandoc, etc.) then re-run.
4. If you expect the type to be supported but still see this, check that failed imports of converters are not silently disabling them (inspect the markitdown converters list).

Example fix

// before
result = md.convert("report.dat")  # no converter accepts .dat

// after
# convert to a supported container first, then:
result = md.convert("report.docx")

SUPPORTED_HINTS = (".pdf", ".docx", ".pptx", ".xlsx", ".csv", ".html", ".htm", ".txt", ".md", ".xml", ".zip", ".mp3", ".wav")

def probably_convertible(path: str) -> bool:
    return os.path.splitext(path)[1].lower() in SUPPORTED_HINTS

from markitdown import _markitdown.UnsupportedFormatException
try:
    result = md.convert(path)
except Exception as e:
    if type(e).__name__ == "UnsupportedFormatException":
        logger.info("skipping unsupported file %s", path)
        return None
    raise

When it happens

Trigger: Calling convert()/convert_stream() on a file whose (extension, mimetype, content) signature matches no registered converter — e.g. a proprietary binary format, a file with a misleading or missing extension, or an empty/garbage file that defeats detection.

Common situations: Users uploading .bin/.dat/.exe or Office/legacy formats not enabled (converters for docx/pdf/xlsx are optional dependencies); a .pdf handled by a converter that failed to import, leaving no accepting converter; a truncated upload where the magic bytes are missing.

Related errors

• MarkItDown requires media to be provided.
• MarkItDown is not installed. Please install it with `pip ins
• url must not be None
• url must be a non-empty string
• url must start with http:// or https://

AI-assisted analysis of xtekky/gpt4free@973504e177 (2026-08-14). Data as JSON: /api/errors/70b28324af7a3868. Report an issue: GitHub.