# `System.EnvError`
[🔗](https://github.com/elixir-lang/elixir/blob/v1.20.1/lib/elixir/lib/system.ex#L70)

An exception raised when a system environment variable is not set.

For example, see `System.fetch_env!/1`.

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*Consult [api-reference.md](api-reference.md) for complete listing*