diff --git a/compressor/conf.py b/compressor/conf.py
index 86e6e72..0697e6b 100644
--- a/compressor/conf.py
+++ b/compressor/conf.py
@@ -77,7 +77,8 @@ class CompressorConf(AppConf):
         if value is None:
             value = settings.STATIC_ROOT
         if value is None:
-            raise ImproperlyConfigured("COMPRESS_ROOT setting must be set")
+            raise ImproperlyConfigured('COMPRESS_ROOT defaults to ' +
+                                       'STATIC_ROOT, please define either')
         return os.path.normcase(os.path.abspath(value))
 
     def configure_url(self, value):