diff --git a/pkg/dataplane/streamconsumergroup/sequencenumberhandler.go b/pkg/dataplane/streamconsumergroup/sequencenumberhandler.go
index 44b6e6f..a22b671 100644
--- a/pkg/dataplane/streamconsumergroup/sequencenumberhandler.go
+++ b/pkg/dataplane/streamconsumergroup/sequencenumberhandler.go
@@ -72,6 +72,10 @@ func (snh *sequenceNumberHandler) stop() error {
 }
 
 func (snh *sequenceNumberHandler) markShardSequenceNumber(shardID int, sequenceNumber uint64) error {
+	err := snh.member.streamConsumerGroup.checkShardExists(shardID, sequenceNumber)
+	if err != nil {
+		return errors.Wrapf(err, "Failed checking shard exists. Current sequenceNumber %v", snh.markedShardSequenceNumbers[shardID])
+	}
 	snh.markedShardSequenceNumbers[shardID] = sequenceNumber
 
 	return nil
diff --git a/pkg/dataplane/streamconsumergroup/streamconsumergroup.go b/pkg/dataplane/streamconsumergroup/streamconsumergroup.go
index 8a21087..f0a0642 100644
--- a/pkg/dataplane/streamconsumergroup/streamconsumergroup.go
+++ b/pkg/dataplane/streamconsumergroup/streamconsumergroup.go
@@ -367,10 +367,36 @@ func (scg *streamConsumerGroup) setShardSequenceNumberInPersistency(shardID int,
 		Attributes: map[string]interface{}{
 			scg.getShardCommittedSequenceNumberAttributeName(): sequenceNumber,
 		},
+		Condition: "__obj_type == 3",
 	})
 	return err
 }
 
+func (scg *streamConsumerGroup) checkShardExists(shardID int, sequenceNumber uint64) error {
+	shardPath, err := scg.getShardPath(shardID)
+	if err != nil {
+		return errors.Wrapf(err, "Failed getting shard path: %v", shardID)
+	}
+
+	response, err := scg.container.GetItemSync(&v3io.GetItemInput{
+		Path: shardPath,
+		AttributeNames: []string{
+			"__obj_type",
+		},
+	})
+	defer response.Release()
+	if err != nil {
+		return errors.Wrapf(err, "Updating shard counter %v to %v failed.Failed to fetch shard object type", shardPath, sequenceNumber)
+	}
+	getItemOutput := response.Output.(*v3io.GetItemOutput)
+
+	objType, err2 := getItemOutput.Item.GetFieldInt("__obj_type")
+	if err2 != nil || objType != 3 {
+		return errors.Wrapf(err2, "Updating shard counter %v to %v failed. Shard is a regular file (%v)", shardPath, sequenceNumber, objType)
+	}
+	return nil
+}
+
 // returns true if the states are equal, ignoring heartbeat times
 func (scg *streamConsumerGroup) statesEqual(state0 *State, state1 *State) bool {
 	if state0.SchemasVersion != state1.SchemasVersion {