diff --git a/src/AssetMapper/SassCssCompiler.php b/src/AssetMapper/SassCssCompiler.php
index 600678c..8270e82 100644
--- a/src/AssetMapper/SassCssCompiler.php
+++ b/src/AssetMapper/SassCssCompiler.php
@@ -40,7 +40,7 @@ public function compile(string $content, MappedAsset $asset, AssetMapperInterfac
 
         $asset->addFileDependency($cssFile);
 
-        if (($content = file_get_contents($cssFile)) === false) {
+        if (!is_file($cssFile) || ($content = file_get_contents($cssFile)) === false) {
             throw new \RuntimeException('The file '.$cssFile.' doesn\'t exist, run php bin/console sass:build');
         }