diff --git a/services/univention-s4-connector/modules/univention/s4connector/s4/dc.py b/services/univention-s4-connector/modules/univention/s4connector/s4/dc.py
index e539189f1c..4882f3b958 100644
--- a/services/univention-s4-connector/modules/univention/s4connector/s4/dc.py
+++ b/services/univention-s4-connector/modules/univention/s4connector/s4/dc.py
@@ -75,6 +75,8 @@ def _s2nano(seconds):
 
 
 def _nano2s(nanoseconds):
+	if nanoseconds == 0x8000000000000000L:
+		return 0
 	return nanoseconds / 10000000