lutzroeder/netron · error · Error

File not found '${file}'.

Error message

File not found '${file}'.

What it means

Thrown by the browser host's memory-backed archive/session when fetch() is called for a key that is not present in the in-memory blob map. The library looks up files by their stored identifier (e.g. an ONNX/protobuf external-data file name) and refuses to proceed if no blob with that exact key was registered. It is the browser equivalent of a missing file on disk.

Source

Thrown at source/browser.js:654

    get identifier() {
        return this._file.name;
    }

    get stream() {
        return this._stream;
    }

    async asset(file) {
        return this._host.asset(file);
    }

    async fetch(file, encoding, basename) {
        if (basename !== undefined) {
            return this._host.fetch(file, encoding, basename);
        }
        const blob = this._blobs[file];
        if (!blob) {
            throw new Error(`File not found '${file}'.`);
        }
        return new Promise((resolve, reject) => {
            const window = this._host.window;
            const reader = new window.FileReader();
            const size = 0x10000000;
            let position = 0;
            const chunks = [];
            reader.onload = (e) => {
                if (encoding) {
                    resolve(e.target.result);
                } else {
                    const buffer = new Uint8Array(e.target.result);
                    if (position === 0 && buffer.length === blob.size) {
                        const stream = new base.BinaryStream(buffer);
                        resolve(stream);
                    } else {
                        chunks.push(buffer);
                        position += buffer.length;

View on GitHub (pinned to d8a543f5f8)

Solutions

1. Verify the exact file name string the model metadata references and pass the same key when registering the blob
2. If the model uses external data files, load every referenced companion file into the session before opening the model
3. Check for path normalization mismatches (leading './', backslashes vs forward slashes, case) between the stored key and the requested key
4. If the file should already exist, inspect the blob map keys (e.g. log Object.keys of the session files) to see what is actually registered

Example fix

// before
const model = await context.open('model.onnx'); // model references 'weights.onnx' not loaded

// after
await context.open('model.onnx', ['weights.onnx']); // supply referenced external files too

// Before opening, ensure every referenced file exists in the session
const required = ['model.onnx', 'weights.onnx'];
const missing = required.filter((f) => !context.has(f)); // or check session blob keys
if (missing.length) {
  await context.request(missing); // prompt user / fetch blobs
}

try {
  const model = await context.open('model.onnx');
} catch (e) {
  if (/File not found/.test(e.message)) {
    // surface an upload prompt for the missing file name parsed from e.message
    const missing = e.message.match(/'(.*)'/)?.[1];
    showFileDialog(missing);
  } else throw e;
}

When it happens

Trigger: Calling context.fetch(file) / session.fetch(file) (directly or indirectly by a model loader resolving external data references) with a file name that was never added to the browser session's blob store, or with a name whose case/path separators differ from the key it was stored under.

Common situations: Loading a model that references external weight files (e.g. ONNX external_data) while only supplying the main .onnx/.pb file; uploading a manifest plus files whose names don't byte-for-byte match the references; loading an archive where the entry path has a leading './' or different case sensitivity.

Understand the failure class

Background: "File not found" and ENOENT errors: why libraries can't find a file that should exist — this error's family across 50 libraries.

AI-assisted analysis of lutzroeder/netron@d8a543f5f8 (2026-08-27). Data as JSON: /api/errors/abf51941f1eab952. Report an issue: GitHub.