diff --git a/code/modules/assembly/signaler.dm b/code/modules/assembly/signaler.dm
index c970cd62d5f..8c6d104ef0e 100644
--- a/code/modules/assembly/signaler.dm
+++ b/code/modules/assembly/signaler.dm
@@ -109,7 +109,9 @@ Code:
 
 	var/time = time2text(world.realtime,"hh:mm:ss")
 	var/turf/T = get_turf(src)
-	lastsignalers.Add("[time] <B>:</B> [usr.key] used [src] @ location ([T.x],[T.y],[T.z]) <B>:</B> [format_frequency(frequency)]/[code]")
+	if(usr)
+		lastsignalers.Add("[time] <B>:</B> [usr.key] used [src] @ location ([T.x],[T.y],[T.z]) <B>:</B> [format_frequency(frequency)]/[code]")
+
 
 	return
 /*