tauri-apps/tauri · error

failed to parse icon

Error message

failed to parse icon {}: {}

What it means

EmbeddedImage::new_ico reads an .ico file and parses it with the `ico` crate during macro expansion. If ico::IconDir::read fails — the file is not a valid ICO container or is truncated/corrupt — the macro panics with this message, naming the icon path and the underlying parse error.

Solutions

1. Regenerate the .ico with a proper converter (e.g. `ImageMagick: magick icon.png -define icon:auto-resize=32,16 icon.ico`)
2. Verify the file starts with the ICO magic bytes 00 00 01 00
3. Re-download or restore the icon from version control
4. Use a PNG icon with ImageFormat::Png instead of ICO

Example fix

// before
cp icon.png icon.ico  // invalid: renamed PNG
// after
magick icon.png -define icon:auto-resize=256,128,64,48,32,16 icon.ico

with open('icon.ico','rb') as f:
    if f.read(4) != b'\x00\x00\x01\x00':
        raise SystemExit('not a valid ICO file')

When it happens

Trigger: Passing an `icon` path whose bytes are not a valid ICO (e.g. a PNG renamed to .ico with a header the parser rejects, or a truncated download) into tauri::icon! / EmbeddedAssets icon handling.

Common situations: Renaming a PNG to .ico instead of converting; icons corrupted by git LFS smudge failure; partially downloaded icon files; icons generated by tools producing unsupported ICO variants.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• failed to decode icon
• failed to open icon
• failed to read icon
• creating icon
• failed to read plist

AI-assisted analysis of tauri-apps/tauri@460ec35447 (2026-09-18). Data as JSON: /api/errors/1b5b0cea1841297a. Report an issue: GitHub.

Appendix: source

Thrown at crates/tauri-codegen/src/image.rs:55

    }
  }

  /// Cache the icon without any manipulation.
  pub fn new_raw(root: &TokenStream, icon: &Path) -> EmbeddedAssetsResult<Self> {
    let buf = Self::open(icon);
    Cached::try_from(buf).map(|cache| Self {
      cache,
      root: root.clone(),
      format: IconFormat::Raw,
    })
  }

  /// Cache an ICO icon as RGBA data, see [`ImageFormat::Image`].
  pub fn new_ico(root: &TokenStream, icon: &Path) -> EmbeddedAssetsResult<Self> {
    let buf = Self::open(icon);

    let icon_dir = ico::IconDir::read(Cursor::new(&buf))
      .unwrap_or_else(|e| panic!("failed to parse icon {}: {}", icon.display(), e));

    let entry = &icon_dir.entries()[0];
    let rgba = entry
      .decode()
      .unwrap_or_else(|e| panic!("failed to decode icon {}: {}", icon.display(), e))
      .rgba_data()
      .to_vec();

    Cached::try_from(rgba).map(|cache| Self {
      cache,
      root: root.clone(),
      format: IconFormat::Image {
        width: entry.width(),
        height: entry.height(),
      },
    })
  }

View on GitHub (pinned to 460ec35447)