diff --git a/proxmox.py b/proxmox.py
index 90193d2..46f893e 100755
--- a/proxmox.py
+++ b/proxmox.py
@@ -370,11 +370,12 @@ def main_list(options, config_path):
 
             if 'proxmox_os_id' in results['_meta']['hostvars'][vm]:
                 osid = results['_meta']['hostvars'][vm]['proxmox_os_id']
-                if osid not in results:
-                    results[osid] = {
-                        'hosts': []
-                    }
-                results[osid]['hosts'] += [vm]
+                if osid:
+                    if osid not in results:
+                        results[osid] = {
+                            'hosts': []
+                        }
+                    results[osid]['hosts'] += [vm]
 
             results['_meta']['hostvars'][vm].update(metadata)