diff --git a/webservice/manual_launch.py b/webservice/manual_launch.py
index a5a53aa9f93ee8322231de145627923741b607b5..3b5bd7eda0f3ca156a76b81da09b01892f2bf462 100644
--- a/webservice/manual_launch.py
+++ b/webservice/manual_launch.py
@@ -173,7 +173,7 @@ def main(
         all_runs = get_runs_by_proposal_all(proposal_no)
 
     run_no_id_map = {run["run_number"]: run["id"] for run in all_runs}
-    max_run_no = max(run_no_id_map.keys())
+    max_run_no = max(run_no_id_map.keys()) + 1
     requested_ranges = [range(*s.indices(max_run_no)) for s in slices]
     requested_run_nos = {run_no for r in requested_ranges for run_no in r}