Index: /trunk/FACT++/src/EventBuilderWrapper.h
===================================================================
--- /trunk/FACT++/src/EventBuilderWrapper.h	(revision 16955)
+++ /trunk/FACT++/src/EventBuilderWrapper.h	(revision 16956)
@@ -127,7 +127,16 @@
 
         // Get current night
-        const uint32_t night = Time().NightAsInt();
+        const Time now;
+
+        const uint32_t night = now.NightAsInt();
         if (night==fNightAsInt)
             return true;
+
+        if (night<fNightAsInt)
+        {
+            fMsg.Warn("New night "+to_string(night)+" ["+now.GetAsStr()+"] before current night "+to_string(night)+"... keeping old one.");
+            fMsg.Warn("Please check the system clock.");
+            return true;
+        }
 
         // Check for run numbers
@@ -161,6 +170,6 @@
             str << "First night...";
         else
-            str << "Night has changd from " << fNightAsInt << "... new";
-        str << " run-number is " << night << "-" << setfill('0') << setw(3) << fRunNumber << " [" << (fPath.empty()?".":fPath) << "]";
+            str << "Night has changed from " << fNightAsInt << " [" << now << "]... ";
+        str << " next run-number is " << night << "-" << setfill('0') << setw(3) << fRunNumber << " [" << (fPath.empty()?".":fPath) << "]";
         fMsg.Message(str);