diff --git a/prometheus-entrouvert-exporter/prometheus-system-exporter.py b/prometheus-entrouvert-exporter/prometheus-system-exporter.py
index d465dcb..e2abeb1 100755
--- a/prometheus-entrouvert-exporter/prometheus-system-exporter.py
+++ b/prometheus-entrouvert-exporter/prometheus-system-exporter.py
@@ -230,8 +230,13 @@ def units(ctn):
     manager = dbus.Interface(s, "org.freedesktop.systemd1.Manager")
     units = manager.ListUnits()
     n = len([u for u in units if u[3] == "failed" and not u[0].startswith("user@")])
-    name = [u[0].replace('dbus.String', '') for u in units if u[3] == "failed" and not u[0].startswith("user@")]
-    eo_units.labels(ctn, name, "failed").set(n)
+    name = [
+        u[0].replace('dbus.String', '') for u in units if u[3] == "failed" and not u[0].startswith("user@")
+    ]
+    if name:
+        eo_units.labels(ctn, name, "failed").set(n)
+    else:
+        eo_units.labels(ctn, "failed").set(n)
 
 
 def run_in_machines(ctn):