diff --git a/weed/server/volume_grpc_erasure_coding.go b/weed/server/volume_grpc_erasure_coding.go
index a90747ba4..6d4ff623e 100644
--- a/weed/server/volume_grpc_erasure_coding.go
+++ b/weed/server/volume_grpc_erasure_coding.go
@@ -324,7 +324,7 @@ func (vs *VolumeServer) VolumeEcShardsUnmount(ctx context.Context, req *volume_s
 	glog.V(0).Infof("VolumeEcShardsUnmount: %v", req)
 
 	for _, shardId := range req.ShardIds {
-		err := vs.store.UnmountEcShards(needle.VolumeId(req.VolumeId), erasure_coding.ShardId(shardId))
+		err := vs.store.UnmountEcShards(needle.VolumeId(req.VolumeId), erasure_coding.ShardId(shardId), req.Generation)
 
 		if err != nil {
 			glog.Errorf("ec shard unmount %v: %v", req, err)
diff --git a/weed/shell/command_ec_common.go b/weed/shell/command_ec_common.go
index 8bef78394..2ed4dd354 100644
--- a/weed/shell/command_ec_common.go
+++ b/weed/shell/command_ec_common.go
@@ -441,8 +441,9 @@ func unmountEcShards(grpcDialOption grpc.DialOption, volumeId needle.VolumeId, s
 
 	return operation.WithVolumeServerClient(false, sourceLocation, grpcDialOption, func(volumeServerClient volume_server_pb.VolumeServerClient) error {
 		_, deleteErr := volumeServerClient.VolumeEcShardsUnmount(context.Background(), &volume_server_pb.VolumeEcShardsUnmountRequest{
-			VolumeId: uint32(volumeId),
-			ShardIds: toBeUnmountedhardIds,
+			VolumeId:   uint32(volumeId),
+			ShardIds:   toBeUnmountedhardIds,
+			Generation: 0, // shell commands operate on existing (generation 0) volumes
 		})
 		return deleteErr
 	})
@@ -457,6 +458,7 @@ func mountEcShards(grpcDialOption grpc.DialOption, collection string, volumeId n
 			VolumeId:   uint32(volumeId),
 			Collection: collection,
 			ShardIds:   toBeMountedhardIds,
+			Generation: 0, // shell commands operate on existing (generation 0) volumes
 		})
 		return mountErr
 	})
diff --git a/weed/storage/store_ec.go b/weed/storage/store_ec.go
index b255ee80d..493ad660d 100644
--- a/weed/storage/store_ec.go
+++ b/weed/storage/store_ec.go
@@ -62,6 +62,7 @@ func (s *Store) MountEcShards(collection string, vid needle.VolumeId, shardId er
 				DiskType:    string(location.DiskType),
 				ExpireAtSec: ecVolume.ExpireAtSec,
 				DiskId:      uint32(diskId),
+				Generation:  generation, // include generation in mount message
 			}
 			return nil
 		} else if err == os.ErrNotExist {
@@ -74,7 +75,7 @@ func (s *Store) MountEcShards(collection string, vid needle.VolumeId, shardId er
 	return fmt.Errorf("MountEcShards %d.%d not found on disk", vid, shardId)
 }
 
-func (s *Store) UnmountEcShards(vid needle.VolumeId, shardId erasure_coding.ShardId) error {
+func (s *Store) UnmountEcShards(vid needle.VolumeId, shardId erasure_coding.ShardId, generation uint32) error {
 
 	diskId, ecShard, found := s.findEcShard(vid, shardId)
 	if !found {
@@ -88,6 +89,7 @@ func (s *Store) UnmountEcShards(vid needle.VolumeId, shardId erasure_coding.Shar
 		EcIndexBits: uint32(shardBits.AddShardId(shardId)),
 		DiskType:    string(ecShard.DiskType),
 		DiskId:      diskId,
+		Generation:  generation, // include generation in unmount message
 	}
 
 	location := s.Locations[diskId]