diff --git a/plugin/migration/util/util.go b/plugin/migration/util/util.go
index 19719674..91d11a8a 100644
--- a/plugin/migration/util/util.go
+++ b/plugin/migration/util/util.go
@@ -89,6 +89,9 @@ func GetMapStringSliceValue(m util.MapStr, key string) []string {
 	if err != nil {
 		return nil
 	}
+	if v == nil {
+		return nil
+	}
 	vv, ok := v.([]string)
 	if !ok {
 		vv, ok := v.([]interface{})