oraios/serena · critical · SolidLSPException

Required .NET runtime version {self._required_version_str} n

Error message

Required .NET runtime version {self._required_version_str} not found (installed versions: {self._installed_versions}). Please install the required .NET runtime version from https://dotnet.microsoft.com/en-us/download/dotnet and ensure that `dotnet` is on the system PATH.

What it means

The DotnetUtil helper verifies that the required .NET runtime version is installed before handing out the dotnet executable path. If is_required_version_available() is False it raises SolidLSPException listing installed versions and pointing to the official download. This is used by language servers (e.g. C#/OmniSharp, Razor) that need dotnet to run.

Source

Thrown at src/serena/util/dotnet.py:66

        """
        required_version_str = ".".join(str(c) for c in self._required_version_components)
        for v in self._installed_versions:
            if self._allow_higher_version:
                if v.is_at_least(*self._required_version_components):
                    log.info(f"Found installed .NET runtime version {v} which satisfies requirement of {required_version_str} or higher")
                    return True
            else:
                if v.is_equal(*self._required_version_components):
                    log.info(f"Found installed .NET runtime version {v} which satisfies requirement of {required_version_str}")
                    return True
        return False

    def get_dotnet_path_or_raise(self) -> str:
        """
        Returns the path to the dotnet executable if the required .NET runtime version is available, otherwise raises an exception.
        """
        if not self.is_required_version_available():
            raise SolidLSPException(
                f"Required .NET runtime version {self._required_version_str} not found "
                f"(installed versions: {self._installed_versions}). "
                "Please install the required .NET runtime version from https://dotnet.microsoft.com/en-us/download/dotnet "
                "and ensure that `dotnet` is on the system PATH."
            )
        assert self._system_dotnet is not None
        return self._system_dotnet

    @staticmethod
    def install_dotnet_with_script(version: str, base_path: str) -> str:
        """
        Install .NET runtime using Microsoft's official installation script.

        NOTE: This method is unreliable and therefore currently unused. It is kept for reference.

        :version: the version to install as a string (e.g. "10.0")
        :return: the path to the dotnet executable.
        """

View on GitHub (pinned to 7fcbca7e62)

Solutions

1. Install the required .NET runtime from https://dotnet.microsoft.com/en-us/download/dotnet
2. Ensure the dotnet executable is on the system PATH (verify with `dotnet --list-runtimes`)
3. Install the exact version required (check _required_version_str, e.g. 6.0/8.0)
4. Or set up dotnet via a package manager: apt/dnf/brew install dotnet-runtime-<version>

Example fix

// before
dotnet --info  # command not found
// after
sudo apt-get install -y dotnet-runtime-8.0
export PATH="$PATH:/usr/share/dotnet"
dotnet --list-runtimes

import shutil, subprocess
if shutil.which("dotnet") is None:
    raise RuntimeError("dotnet not on PATH; install from https://dotnet.microsoft.com/en-us/download/dotnet")
subprocess.run(["dotnet", "--list-runtimes"], check=True, capture_output=True)

try:
    dotnet_path = DotnetUtil(...).get_dotnet_path_or_raise()
except SolidLSPException as e:
    log.error("Install required .NET runtime: %s", e)
    sys.exit(1)

When it happens

Trigger: Starting a language server whose _setup_runtime_dependencies calls _ensure_dotnet_runtime -> get_dotnet_path_or_raise when no dotnet is on PATH or the installed runtime is older/newer than the required version string.

Common situations: Fresh machines without .NET SDK/runtime; dotnet installed but not on PATH; wrong runtime channel (e.g. only ASP.NET Core runtime installed, missing base runtime); version pinned by the language server not present.

Related errors

• dotnet or mono not found on the system
• dotnet executable not found at {dotnet_exe} after installati
• Failed to install .NET {version} runtime: {e}
• Could not find 'uvx' or 'uv' in PATH. Install uv (https://do
• Failed to locate or download AL Language Server. Please eith

AI-assisted analysis of oraios/serena@7fcbca7e62 (2026-08-29). Data as JSON: /api/errors/3e853b1663279d06. Report an issue: GitHub.