Module not found: Error: Can't resolve 'vue-router'

This error usually occurs when the `vue-router` package is not installed in your project or is not properly imported into your file.

To resolve this error, first make sure that `vue-router` is installed as a dependency in your project. You can install it using npm or yarn:

npm install vue-router --save

or

yarn add vue-router

Once it's installed, you can import it in your code like this:

import VueRouter from 'vue-router'

Make sure that the path to `vue-router` is correct and that you have saved the changes to your file before trying to run your project again.