diff --git a/debian/alternc-slave.config b/debian/alternc-slave.config
index 0caff15f..e4ec439f 100644
--- a/debian/alternc-slave.config
+++ b/debian/alternc-slave.config
@@ -149,7 +149,7 @@ db_set alternc-slave/alternc_location "$ALTERNC_LOC"
 fi
 
 # backward compatbility
-db_get alternc-slave/mergelog-key
+db_get alternc-slave/mergelog-key || true
 [ -z "$RET" ] || db_set alternc-slave/master-key "$RET"
 
 db_input medium alternc-slave/desktopname || true