Index: lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/GradebookService.java
===================================================================
diff -u -rd72e0ae576eae16c7e1104e90cfb3770dd5f3282 -r3575c1543b82a29a6aeeb5c61ac0970a51bfd30b
--- lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/GradebookService.java	(.../GradebookService.java)	(revision d72e0ae576eae16c7e1104e90cfb3770dd5f3282)
+++ lams_gradebook/src/java/org/lamsfoundation/lams/gradebook/service/GradebookService.java	(.../GradebookService.java)	(revision 3575c1543b82a29a6aeeb5c61ac0970a51bfd30b)
@@ -2474,7 +2474,7 @@
 		: 0.0;
 
 	for (GradebookUserActivity guact : userActivities) {
-	    if (markedActivity == null || guact.getUid() != markedActivity.getUid()) {
+	    if (guact.getMark() != null && (markedActivity == null || guact.getUid() != markedActivity.getUid())) {
 		if (useWeightings) {
 		    totalMark = totalMark + getWeightedMark(useWeightings, guact, guact.getMark());
 		} else {