diff --git a/package.json b/package.json
index b14b0b1..8c70c37 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "grunt-cache-bust",
   "description": "Bust static assets from the cache using content hashing",
-  "version": "0.4.2",
+  "version": "0.4.3",
   "author": "Ben Holland <hi@benholland.me>",
   "repository": {
     "type": "git",
diff --git a/tasks/cachebust.js b/tasks/cachebust.js
index a15948a..aaf42f9 100644
--- a/tasks/cachebust.js
+++ b/tasks/cachebust.js
@@ -89,17 +89,21 @@ module.exports = function(grunt) {
             var cssObj = css.parse(data);
 
             // Loop through each stylesheet rules
-            cssObj.stylesheet.rules.forEach(function(rule) {
+            if(cssObj.stylesheet) {
+                cssObj.stylesheet.rules.forEach(function(rule) {
 
-                // Loop through all declarations
-                rule.declarations.forEach(function(declaration) {
+                    // Loop through all declarations
+                    if(rule.declarations) {
+                        rule.declarations.forEach(function(declaration) {
 
-                    // Check if it has a background property, and if so, checkt that it contains a URL
-                    if((/background/).test(declaration.property) && (/url/).test(declaration.value)) {
-                        paths.push(declaration.value.match(/url\(["|']?(.*?)['|"]?\)/)[1]);
+                            // Check if it has a background property, and if so, checkt that it contains a URL
+                            if((/background/).test(declaration.property) && (/url/).test(declaration.value)) {
+                                paths.push(declaration.value.match(/url\(["|']?(.*?)['|"]?\)/)[1]);
+                            }
+                        });
                     }
                 });
-            });
+            }
         } else {
             // Add any conditional statements or assets in comments to the DOM
             var assets = '';