diff --git a/.github/contributing.md b/.github/contributing.md
index 9f595f28..f890f31c 100644
--- a/.github/contributing.md
+++ b/.github/contributing.md
@@ -39,7 +39,7 @@ Hi! I'm really excited that you are interested in contributing to Vue.js. Before
 
 ## Development Setup
 
-You will need [Node.js](http://nodejs.org) **version 10+**, and [Yarn](https://yarnpkg.com/en/docs/install).
+You will need [Node.js](http://nodejs.org) **version 10+**, and [Yarn 1.x](https://yarnpkg.com/en/docs/install).
 
 After cloning the repo, run:
 
diff --git a/scripts/checkYarn.js b/scripts/checkYarn.js
index 19d9f515..26a385e0 100644
--- a/scripts/checkYarn.js
+++ b/scripts/checkYarn.js
@@ -1,5 +1,6 @@
 if (!/yarn\.js$/.test(process.env.npm_execpath || '')) {
   console.warn(
-    "\u001b[33mYou don't seem to be using yarn. This could produce unexpected results.\u001b[39m"
+    '\u001b[33mThis repository requires Yarn 1.x for scripts to work properly.\u001b[39m\n'
   )
+  process.exit(1)
 }