diff --git a/src/PatchOrchestrationApplication/CoordinatorService/src/RepairManagerHelper.cs b/src/PatchOrchestrationApplication/CoordinatorService/src/RepairManagerHelper.cs
index ebdabb1..4def4fd 100644
--- a/src/PatchOrchestrationApplication/CoordinatorService/src/RepairManagerHelper.cs
+++ b/src/PatchOrchestrationApplication/CoordinatorService/src/RepairManagerHelper.cs
@@ -558,7 +558,7 @@ internal async Task PrepareRepairTasks(CancellationToken cancellationToken)
                                 if (completedTasks.Any())
                                 {
                                     RepairTask lastCompletedTask = completedTasks.Aggregate((curMax, task) => (task.CompletedTimestamp > curMax.CompletedTimestamp ? task : curMax));
-                                    timePastAfterCompletedTask = DateTime.UtcNow - lastCompletedTask.CompletedTimestamp;
+                                    timePastAfterCompletedTask = DateTime.UtcNow - lastCompletedTask?.CompletedTimestamp;
                                 }