diff --git a/MatrixSDK/Data/MXRoom.m b/MatrixSDK/Data/MXRoom.m
index 1349a8c5fa..c989074c83 100644
--- a/MatrixSDK/Data/MXRoom.m
+++ b/MatrixSDK/Data/MXRoom.m
@@ -2001,7 +2001,9 @@ - (void)markAllAsRead
     NSString *readMarkerEventId = nil;
     MXReceiptData *updatedReceiptData = nil;
     
-    NSString *lastMessageEventId = self.summary.lastMessageEvent.eventId;
+    // Retrieve the most recent event of the room.
+    MXEvent *lastEvent = [mxSession.store messagesEnumeratorForRoom:self.roomId].nextEvent;
+    NSString *lastMessageEventId = lastEvent.eventId;
     
     // Sanity check: Do not send read marker on event without id.
     if (!lastMessageEventId || [lastMessageEventId hasPrefix:kMXRoomInviteStateEventIdPrefix])
@@ -2048,6 +2050,9 @@ - (void)markAllAsRead
                         }
                     }
                 }
+                
+                // Break the loop
+                break;
             }
         }
     }
diff --git a/MatrixSDK/Data/MXRoomSummary.h b/MatrixSDK/Data/MXRoomSummary.h
index 0b003062f6..26002d807f 100644
--- a/MatrixSDK/Data/MXRoomSummary.h
+++ b/MatrixSDK/Data/MXRoomSummary.h
@@ -122,7 +122,7 @@ FOUNDATION_EXPORT NSString *const kMXRoomSummaryDidChangeNotification;
 #pragma mark - Data related to room state
 
 /**
- The avatar url of the room.
+ The Matrix content URI of the room avatar.
  */
 @property (nonatomic) NSString *avatar;