diff --git a/scripts/vm/hypervisor/xenserver/s3xen b/scripts/vm/hypervisor/xenserver/s3xen
index 44a30efd4b3..a87e6de5dbe 100644
--- a/scripts/vm/hypervisor/xenserver/s3xen
+++ b/scripts/vm/hypervisor/xenserver/s3xen
@@ -352,7 +352,7 @@ def s3(session, args):
             client.delete(bucket, key, filename)
         else:
             raise RuntimeError(
-                "S3 plugin does not support operation {0}.".format(operation))
+                "S3 plugin does not support operation " + operation))
 
         return 'true'