nautechsystems/nautilus_trader · error

Cannot unsubscribe from synthetic instrument `Instrument` da

Error message

Cannot unsubscribe from synthetic instrument `Instrument` data

What it means

Unsubscribing from `Instrument` data is only valid for real instruments; for a synthetic instrument ID the engine never had a client subscription to remove, so UnsubscribeCommand::Instrument targeting a synthetic ID bails with this error. (Synthetic Trades unsubscribes are handled separately and succeed.)

Source

Thrown at crates/data/src/engine/mod.rs:1271

                self.unsubscribe_option_chain(cmd);
                return Ok(());
            }
            UnsubscribeCommand::Quotes(cmd) if cmd.instrument_id.is_synthetic() => {
                self.unsubscribe_synthetic_quotes(cmd.instrument_id);
                return Ok(());
            }
            UnsubscribeCommand::Quotes(cmd)
                if self.is_spread_quote_command(cmd.instrument_id, cmd.params.as_ref()) =>
            {
                self.unsubscribe_spread_quotes(cmd);
                return Ok(());
            }
            UnsubscribeCommand::Trades(cmd) if cmd.instrument_id.is_synthetic() => {
                self.unsubscribe_synthetic_trades(cmd.instrument_id);
                return Ok(());
            }
            UnsubscribeCommand::Instrument(cmd) if cmd.instrument_id.is_synthetic() => {
                anyhow::bail!("Cannot unsubscribe from synthetic instrument `Instrument` data");
            }
            UnsubscribeCommand::InstrumentStatus(cmd) if cmd.instrument_id.is_synthetic() => {
                anyhow::bail!(
                    "Cannot unsubscribe from synthetic instrument `InstrumentStatus` data"
                );
            }
            UnsubscribeCommand::InstrumentClose(cmd) if cmd.instrument_id.is_synthetic() => {
                anyhow::bail!(
                    "Cannot unsubscribe from synthetic instrument `InstrumentClose` data"
                );
            }
            UnsubscribeCommand::OptionGreeks(cmd) if cmd.instrument_id.is_synthetic() => {
                anyhow::bail!("Cannot unsubscribe from synthetic instrument `OptionGreeks` data");
            }
            _ => {}
        }

        if let Some(client) = self.get_command_client(cmd.client_id(), cmd.venue()) {

View on GitHub (pinned to 18893faf8b)

Solutions

1. Skip synthetic instrument IDs in Instrument unsubscribe calls (guard with is_synthetic()).
2. Track which streams were actually subscribed and unsubscribe only those.
3. For synthetic data, use the supported unsubscribe path (synthetic Trades) or simply drop the synthetic generator state.

Example fix

// before
engine.unsubscribe_instruments(synthetic_id)?;
// after
if !synthetic_id.is_synthetic() {
    engine.unsubscribe_instruments(synthetic_id)?;
}

// Rust
if !instrument_id.is_synthetic() {
    engine.unsubscribe_instruments(instrument_id)?;
}

// Rust
fn needs_instrument_unsubscribe(id: &InstrumentId) -> bool {
    !id.is_synthetic()
}

// Rust
match engine.unsubscribe_instruments(id) {
    Err(e) if e.to_string().contains("unsubscribe from synthetic instrument `Instrument`") => Ok(()),
    r => r,
}

When it happens

Trigger: Calling unsubscribe (UnsubscribeCommand::Instrument) with a synthetic InstrumentId — often during teardown code that unsubscribes everything it ever subscribed, or symmetric subscribe/unsubscribe helpers.

Common situations: Cleanup paths that mirror-subscribe all data types; strategy shutdown code iterating over a mixed list of real and synthetic instrument IDs.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Cannot unsubscribe from synthetic instrument `InstrumentStat
• Cannot unsubscribe from synthetic instrument `InstrumentClos
• Cannot subscribe for synthetic instrument `Instrument` data
• Cannot subscribe for synthetic instrument `InstrumentStatus`
• Cannot subscribe for synthetic instrument `InstrumentClose`

AI-assisted analysis of nautechsystems/nautilus_trader@18893faf8b (2026-09-08). Data as JSON: /api/errors/b7b240452f8fa32c. Report an issue: GitHub.