diff --git a/src/common/dao/clair/base.go b/src/common/dao/clair/base.go
index ca67aaa9c..9f952af4f 100644
--- a/src/common/dao/clair/base.go
+++ b/src/common/dao/clair/base.go
@@ -65,5 +65,9 @@ func GetLastUpdate() (int64, error) {
 		}
 		return res, nil
 	}
+	if num > 1 {
+		return 0, fmt.Errorf("Multiple entries for %s in Clair DB", updaterLast)
+	}
+	//num is zero, it's not updated yet.
 	return 0, nil
 }