diff --git a/NEWS b/NEWS
index f452a937..6d85753e 100644
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,10 @@ Enhancements and new features:
 
     * Highlight max stats in the processes list (issue #878)
 
+Bugs corrected:
+
+    * Glances RAID plugin Traceback (issue #927)
+
 Version 2.7.1
 =============
 
diff --git a/glances/plugins/glances_raid.py b/glances/plugins/glances_raid.py
index 7dd8f965..d69ed08f 100644
--- a/glances/plugins/glances_raid.py
+++ b/glances/plugins/glances_raid.py
@@ -145,6 +145,8 @@ class Plugin(GlancesPlugin):
         """
         if status == 'inactive':
             return 'CRITICAL'
-        if used < available:
+        if used is None or available is None:
+            return 'DEFAULT'
+        elif used < available:
             return 'WARNING'
         return 'OK'