Problem: When developing using Ruby and Rails and you start up a Rails Server using command: rails s -p 3012  surprisingly the application would start but then breaks with an error "File to import not found or unreadable: font-awesome". Solution: Check in your project File System/Folder Structure if you have any other depedencies defined in a package.json. This is important because big applications might have depedencies defined for the Server-Side as well as the Front-End.  - Looking at the error, it is clear that this error tells you exactly what the dependency is "font-awesome" now that we know where to start looking (which is the front-end package.json) to make sure those packages are installed. - Look in your project again and find what Dependency management tool the Development Team used when developing the application, e.g. Yarn/Bower or NPM, after finding out what Dependency Management tool was used to install dependencies, make sure that tool is installed on you Development Machine.  - After the above has been verified, it's time to install the dependencies in the packages.json: Navigat to the root of the project and type: yarn install or npm install - Start Rails Server again and see if your application Loads. If the application does not render CSS or any Image Assets see another article that talks about CSS not rendering in Ruby and Rails.