AL Language Server executable not found at: {executable_path

Error message

AL Language Server executable not found at: {executable_path}

What it means

After locating the AL extension directory, _setup_runtime_dependencies builds the expected path to Microsoft.Dynamics.Nav.EditorServices.Host for the current platform. RuntimeError is raised when that binary does not exist inside the extension — meaning the extension folder was found but is incomplete, of an unexpected version/layout, or the wrong platform variant.

Source

Thrown at src/solidlsp/language_servers/al_language_server.py:215

        # Find existing extension or download if needed
        extension_path = cls._find_al_extension(solidlsp_settings)
        if extension_path is None:
            log.info("AL extension not found on disk, attempting to download...")
            extension_path = cls._download_and_install_al_extension(solidlsp_settings)

        if extension_path is None:
            raise RuntimeError(
                "Failed to locate or download AL Language Server. Please either:\n"
                "1. Set AL_EXTENSION_PATH environment variable to the AL extension directory\n"
                "2. Install the AL extension in VS Code (ms-dynamics-smb.al)\n"
                "3. Ensure internet connection for automatic download"
            )

        # Build executable path based on platform
        executable_path = cls._get_executable_path(extension_path, system)

        if not os.path.exists(executable_path):
            raise RuntimeError(f"AL Language Server executable not found at: {executable_path}")

        # Prepare and return the executable command
        return cls._prepare_executable(executable_path, system)

    @classmethod
    def _find_al_extension(cls, solidlsp_settings: SolidLSPSettings) -> str | None:
        """
        Find AL extension in various locations.

        Search order:
        1. Environment variable (AL_EXTENSION_PATH)
        2. Default download location (~/.serena/ls_resources/al-extension)
        3. VS Code installed extensions

        Returns:
            Path to AL extension directory or None if not found

        """

View on GitHub (pinned to 7fcbca7e62)

Solutions

Reinstall the AL extension (or re-download it) to get a complete bin/ directory, then retry.
Verify the expected binary exists: <extension>/bin/{win32|linux|darwin}/Microsoft.Dynamics.Nav.EditorServices.Host(.exe).
Point AL_EXTENSION_PATH at a complete, platform-matching extension directory.

Example fix

// before
export AL_EXTENSION_PATH="/opt/al-src"   # source checkout, no bin/
// after
export AL_EXTENSION_PATH="$HOME/.vscode/extensions/ms-dynamics-smb.al-1.x.x"

Defensive patterns

Strategy: validation

Validate before calling

import os, sys
def al_binary_present(extension_path: str) -> bool:
    system = {'Windows': 'win32', 'Linux': 'linux', 'Darwin': 'darwin'}[sys.platform if sys.platform != 'win32' else 'Windows']
    name = 'Microsoft.Dynamics.Nav.EditorServices.Host' + ('.exe' if system == 'win32' else '')
    return os.path.isfile(os.path.join(extension_path, 'bin', system, name))

Type guard

def is_complete_extension(extension_path: str) -> bool:
    return os.path.isdir(os.path.join(extension_path, 'bin', 'linux')) or \
           os.path.isdir(os.path.join(extension_path, 'bin', 'darwin')) or \
           os.path.isdir(os.path.join(extension_path, 'bin', 'win32'))

Try / catch

try:
    server = ALLanguageServer(...)
except RuntimeError as e:
    if 'executable not found at' in str(e):
        reinstall_al_extension()  # code --install-extension after uninstall
        server = ALLanguageServer(...)
    else:
        raise

Prevention

After installing or updating the AL extension, verify the bin/<platform> directory contains the host binary.
Never point AL_EXTENSION_PATH at source checkouts or partially copied folders.
Match the extension platform to the host OS (don't reuse Windows extension snapshots on Linux).

When it happens

Trigger: AL extension directory resolved successfully but _get_executable_path result fails os.path.exists — e.g. a partial/failed extension install, an extension update that changed bin/ layout, or AL_EXTENSION_PATH pointing at the wrong directory.

Common situations: Manually downloaded/copyied extension folders missing the bin/<platform> subdirectory; Linux servers given a Windows-only extension snapshot; interrupted extension installation.

Related errors

AI-assisted analysis of oraios/serena@7fcbca7e62 (2026-08-29). Data as JSON: /api/errors/76a015dc86c59705. Report an issue: GitHub.