diff --git a/lib/tasks/mkdocs/build.js b/lib/tasks/mkdocs/build.js
index 2e26f9d1c..545f6632c 100644
--- a/lib/tasks/mkdocs/build.js
+++ b/lib/tasks/mkdocs/build.js
@@ -28,6 +28,9 @@ import child from "child_process"
 
 export default () => {
   return () => {
-    return child.spawnSync("mkdocs", ["build"])
+    const proc = child.spawnSync("mkdocs", ["build"])
+    if (proc.status)
+      throw new Error(`MkDocs error:\n${proc.stderr.toString()}`)
+    return proc
   }
 }