diff --git a/PVE/Storage/Plugin.pm b/PVE/Storage/Plugin.pm
index ed71fe4..6b79e7a 100644
--- a/PVE/Storage/Plugin.pm
+++ b/PVE/Storage/Plugin.pm
@@ -742,6 +742,8 @@ sub file_size_info {
 	});
     };
 
+    warn $@ if $@;
+
     return wantarray ? ($size, $format, $used, $parent) : $size;
 }