diff --git a/lib/build.js b/lib/build.js
index 8463b6d690..02c1de03b8 100644
--- a/lib/build.js
+++ b/lib/build.js
@@ -198,6 +198,7 @@ function _generateCssSync (sassPath, cssPath, options = {}) {
         quietDeps: true,
         loadPaths: [projectDir],
         sourceMap: true,
+        sourceMapIncludeSources: true,
         style: 'expanded'
       })
 
diff --git a/lib/errorServer.js b/lib/errorServer.js
index f21384adb6..8b30c637fd 100644
--- a/lib/errorServer.js
+++ b/lib/errorServer.js
@@ -28,6 +28,7 @@ function runErrorServer (error) {
     css: 'text/css',
     ico: 'image/x-icon',
     js: 'text/javascript',
+    map: 'application/json',
     mjs: 'text/javascript',
     png: 'image/png',
     svg: 'image/svg+xml',