`uv sync --frozen` requires a script lockfile; run `{}` to l

Error message

`uv sync --frozen` requires a script lockfile; run `{}` to lock the script

What it means

Error "`uv sync --frozen` requires a script lockfile; run `{}` to lock the script" thrown in astral-sh/uv.

Source

Thrown at crates/uv/src/commands/project/sync.rs:230

        dry_run: dry_run.enabled(),
        environment: EnvironmentReport::from(&environment),
        action: SyncAction::from(&environment),
        target: TargetName::from(&target),
        changes: PackageChangesReport::default(),
    };

    // Show the intermediate results if relevant
    if let Some(message) = sync_report.format(output_format) {
        writeln!(printer.stderr(), "{message}")?;
    }

    // Special-case: we're syncing a script that doesn't have an associated lockfile. In that case,
    // we don't create a lockfile, so the resolve-and-install semantics are different.
    if let SyncTarget::Script(script) = &target {
        let lockfile = LockTarget::from(script).lock_path();
        if !lockfile.is_file() {
            if frozen.is_some() {
                return Err(anyhow::anyhow!(
                    "`uv sync --frozen` requires a script lockfile; run `{}` to lock the script",
                    format!("uv lock --script {}", script.path.user_display()).green(),
                ));
            }

            if let LockCheck::Enabled(lock_check) = lock_check {
                return Err(anyhow::anyhow!(
                    "`uv sync {lock_check}` requires a script lockfile; run `{}` to lock the script",
                    format!("uv lock --script {}", script.path.user_display()).green(),
                ));
            }

            // Parse the requirements from the script.
            let spec = script_specification(
                script.into(),
                &settings.resolver,
                cache,
                workspace_cache,

View on GitHub (pinned to f1a42680ff)

When it happens

Trigger: Thrown at crates/uv/src/commands/project/sync.rs:230 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of astral-sh/uv@f1a42680ff (2026-08-16). Data as JSON: /api/errors/59da58f3b2d82572. Report an issue: GitHub.