# EM_LEAF_UNSUPPORTED

An execution setting is not available yet on either engine.

## What happened

One of this run's execution settings is not available yet on Forge's classic engine or on its newer one. Before a run starts, the engine settles every setting it depends on, and a setting that cannot be settled ends the run with this code without testing anything. The engine's own text is in `detail.reason`.

## What to do

Turn that setting off, or leave it at its default value.

## Example

```json
{
  "status": "failed",
  "error": {
    "code": "EM_LEAF_UNSUPPORTED",
    "message": "The engine refused this run's settings before it started.",
    "detail": {}
  }
}
```

The reply also carries `detail.reason`, left out of this sample.