# error.Error.SessionExists

- **Module:** error.Error
- **Package:** libtmux
- **Language:** Rust
- **Kind:** constant
- **Source:** https://github.com/libtmux/libtmux-rs/blob/f0e37052c232636b61d095817046e6bfc8f2ca40/crates/libtmux/src/error.rs#L614
- **Page:** https://libtmux.org/en/rs/latest/reference/error-error-sessionexists/

A session of this name already exists.

Classified rather than left as a generic refusal because it is the one
creation failure a caller routinely expects and handles: it means "pick
another name", not "tmux is broken". Checking with `has-session` first
would race, since another process can take the name in between.