# Diagnose common setup failures [Back to Engine repository](https://rustic-game-engine.pages.dev/markdown/open-source/engine.md). - Wrong Rust version: run commands in `engine/Engine` and compare `rustup show active-toolchain` with `rust-toolchain.toml`. - Linker or window-system errors: install native build tools and the [platform dependencies](https://rustic-game-engine.pages.dev/markdown/open-source/engine/prerequisites.md). - `cargo deny` unavailable: install the pinned `cargo-deny` version and rerun `doctor`. - An optional gameplay language is reported unavailable: install that language's toolchain and follow its guide; that is different from a missing Rust build prerequisite. - GUI launch fails in a headless environment: use the CI smoke-test setup or launch in a desktop session with working graphics. Return to the [open-source repository directory](https://rustic-game-engine.pages.dev/markdown/open-source.md) for docs, examples, and hosting SDK guides.