bevyengine/bevy · error · MissingProcessedAssetWriterError

Asset Source '{0}' does not have a processed AssetWriter.

Error message

Asset Source '{0}' does not have a processed AssetWriter.

What it means

MissingProcessedAssetWriterError: a processed AssetWriter was requested for an asset source that does not define one. The processing pipeline cannot write processed asset output for this source.

Source

Thrown at crates/bevy_asset/src/io/source.rs:667

/// An error returned when an [`AssetSource`] does not exist for a given id.
#[derive(Error, Debug, Clone, PartialEq, Eq)]
#[error("Asset Source '{0}' does not exist")]
pub struct MissingAssetSourceError(AssetSourceId<'static>);

/// An error returned when an [`AssetWriter`](crate::io::AssetWriter) does not exist for a given id.
#[derive(Error, Debug, Clone)]
#[error("Asset Source '{0}' does not have an AssetWriter.")]
pub struct MissingAssetWriterError(AssetSourceId<'static>);

/// An error returned when a processed [`AssetReader`](crate::io::AssetReader) does not exist for a given id.
#[derive(Error, Debug, Clone, PartialEq, Eq)]
#[error("Asset Source '{0}' does not have a processed AssetReader.")]
pub struct MissingProcessedAssetReaderError(AssetSourceId<'static>);

/// An error returned when a processed [`AssetWriter`](crate::io::AssetWriter) does not exist for a given id.
#[derive(Error, Debug, Clone)]
#[error("Asset Source '{0}' does not have a processed AssetWriter.")]
pub struct MissingProcessedAssetWriterError(AssetSourceId<'static>);

const MISSING_DEFAULT_SOURCE: &str =
    "A default AssetSource is required. Add one to `AssetSourceBuilders`";

View on GitHub (pinned to 396ca72708)

Solutions

1. Add a processed writer (with_processed_writer) when registering the asset source
2. Ensure the asset processor is configured to run for that source
3. Skip processed writes for sources intentionally lacking a processing pipeline

When it happens

Trigger: Thrown at crates/bevy_asset/src/io/source.rs:667 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of bevyengine/bevy@396ca72708 (2026-08-20). Data as JSON: /api/errors/6785a8ce8dba1d36. Report an issue: GitHub.