'BROWSER' is not recognized as an internal or external command,
There are two fixes i found that works perfectly well first one : install cross-env (npm package)npm install cross-env then you change your dev script to
"electron-dev": "concurrently "cross-env BROWSER=none yarn start" "wait-on http://localhost:3000 && electron ."",
please note that you also have to install concurrently if not already installed
second one : install concurrently and run this (on windows though)
"electron-dev": "concurrently "SET BROWSER=none&&npm run start" "wait-on http://localhost:3000 && electron .""