diff --git a/proxmoxlib.py b/proxmoxlib.py
index ecc013e..4975d68 100755
--- a/proxmoxlib.py
+++ b/proxmoxlib.py
@@ -853,7 +853,7 @@ def migrate_vms(self, target_node, filter_name=None, vmid=None) -> None:
 
     def set_tags(self, tags="", filter_name=None) -> None:
         """set virtual machine tags"""
-        vms = self.get_vms(output_format="json", filter_name=filter_name)
+        vms = self.get_vms(output_format="internal", filter_name=filter_name)
         vms = [] if not vms else vms
         for virtual_machine in vms:
             node = self.proxmox_instance.nodes(virtual_machine["node"])