diff --git a/libreplan-webapp/src/main/java/org/libreplan/web/montecarlo/MonteCarloController.java b/libreplan-webapp/src/main/java/org/libreplan/web/montecarlo/MonteCarloController.java
index 7cfc90a1f..97507ac73 100644
--- a/libreplan-webapp/src/main/java/org/libreplan/web/montecarlo/MonteCarloController.java
+++ b/libreplan-webapp/src/main/java/org/libreplan/web/montecarlo/MonteCarloController.java
@@ -301,6 +301,7 @@ public class MonteCarloController extends GenericForwardComposer {
             feedCriticalPathsList();
             reloadGridCritialPathTasks();
         }
+        btnRunMonteCarlo.setDisabled(criticalPath.isEmpty());
     }
 
     private static class CriticalPathTasksRender implements RowRenderer {