RDDT0003: Rolldown Build Process Failed to Start

Message

Failed to start the Rolldown build process: {error}

Cause

The Rolldown DevTools "Run build with devtools" button spawns a vite build child process (with Rolldown's devtools output forced on) so it can surface the resulting session. This diagnostic is thrown when that child process cannot be spawned — for example, when the vite binary cannot be resolved from the project root, or the terminal host fails to launch it.

Example

Clicking "Run build with devtools" in a project where vite is not installed, or where the project root cannot run vite build.

Fix

1. Ensure vite is installed in the project and vite build runs from the project root.
2. Run the build once from a terminal to confirm it succeeds, then retry from DevTools.

Source

• packages/rolldown/src/node/rolldown/build-runner.ts — startBuild() throws this when ctx.terminals.startChildProcess fails to spawn vite build.