diff --git a/weed/storage/volume_vacuum.go b/weed/storage/volume_vacuum.go
index 2c20ce634..6a551bfe7 100644
--- a/weed/storage/volume_vacuum.go
+++ b/weed/storage/volume_vacuum.go
@@ -117,6 +117,9 @@ func (v *Volume) CompactByIndex(opts *CompactOptions) error {
 	if v.DataBackend == nil {
 		return fmt.Errorf("volume %d backend is empty remote:%v", v.Id, v.HasRemoteFile())
 	}
+	if v.nm == nil {
+		return fmt.Errorf("volume %d needle map is nil", v.Id)
+	}
 	if err := v.DataBackend.Sync(); err != nil {
 		glog.V(0).Infof("compact2 failed to sync volume dat %d: %v", v.Id, err)
 	}