Salesforce Illuminated Cloud : UI Bundle Build Failed, Failed to find the npm executable required to build UI bundles.

Same for me, but fails for any lwc component containing html. JS only service components deploy just fine.

This usually means npm isn't installed, isn't in the system PATH, or isn't accessible to the deployment process. Verify the Node.js/npm installation and check the deployment logs for more details.

This error means the deployment process can’t find npm to build your UI bundles.

Check that Node.js/npm is installed on your machine:

node -v
npm -v

If missing, install Node.js, restart VS Code/terminal, and try again. Also run npm install in your project folder if dependencies are missing.

It’s usually an issue with the local deployment environment, not the sandbox.