Use the API to fetch a task.
public virtual void FetchTaskInstance(int activityInstanceId, int userId) { IWorkflowExecutionService exe = WorkflowRuntime.Engine.GetServiceWithCheck<IWorkflowExecutionService>(); ActivityInstance activityInstance = exe.GetActivityInstance(activityInstanceId); if (activityInstance.FetchedById.HasValue && activityInstance.FetchedById.Value > 0) { return; } TaskInstance taskInstance = activityInstance.MessagesInstances.FirstOrDefault( t => t.ToId == userId) as TaskInstance; if (taskInstance == null) { return; } TaskExecutor taskExecutor = new TaskExecutor(taskInstance); taskExecutor.Fetch(); }