pnpm install fails in CI with 'ERR_PNPM_OUTDATED_LOCKFILE Cannot install with "frozen-lockfile" because pnpm-lock.yaml is not up to date with package.json'. How do I fix it?

Cause: In CI environments pnpm defaults to frozen-lockfile mode, meaning it must install exactly what pnpm-lock.yaml describes and refuses to modify it. The error says package.json (or a workspace package, override or patch setting) was changed without the lockfile being regenerated, so the two disagree. Locally the same command quietly updates the lockfile, which is why it "works on my machine". Fix (best first): 1. Run pnpm install locally with the same pnpm version as CI, and commit the updated pnpm-lock.yaml together with the package.json change. This is the intended fix. 2. Align the pnpm version. A different major version can write a different lockfile format or refuse to rewrite a newer one. Pin it with the packageManager field in package.json and make CI honor it (for example the pnpm setup action reads that field), instead of floating to latest. 3. If you changed overrides, patchedDependencies, or workspace package versions, those also live in the lockfile; reinstall to refresh it. 4. Check merge conflicts: after resolving conflicts in package.json, rerun pnpm install rather than hand-editing the lockfile. 5. Use pnpm install --no-frozen-lockfile in CI only when you deliberately want CI to modify the lockfile (for example a bot that updates dependencies). Using it as a blanket fix removes reproducibility, since builds can silently pick new versions. Verify: pnpm install --frozen-lockfile succeeds locally with a clean checkout, then the CI job passes with no lockfile change shown in git status afterwards. Sources: https://pnpm.io/cli/install https://pnpm.io/continuous-integration