diff --git a/src/CoreBundle/Tool/ToolChain.php b/src/CoreBundle/Tool/ToolChain.php
index dfb36d09ea..6e55abe375 100644
--- a/src/CoreBundle/Tool/ToolChain.php
+++ b/src/CoreBundle/Tool/ToolChain.php
@@ -181,18 +181,19 @@ class ToolChain
 
             /** @var Tool $toolEntity */
             $toolEntity = $toolRepo->findOneBy($criteria);
-            $position = $toolList[$tool->getName()] + 1;
-
-            $courseTool = (new CTool())
-                ->setTool($toolEntity)
-                ->setName($tool->getName())
-                ->setPosition($position)
-                ->setVisibility($visibility)
-                ->setParent($course)
-                ->setCreator($course->getCreator())
-                ->addCourseLink($course)
-            ;
-            $course->addTool($courseTool);
+            if ($toolEntity) {
+                $position = $toolList[$tool->getName()] + 1;
+
+                $courseTool = (new CTool())
+                    ->setTool($toolEntity)
+                    ->setName($tool->getName())
+                    ->setPosition($position)
+                    ->setVisibility($visibility)
+                    ->setParent($course)
+                    ->setCreator($course->getCreator())
+                    ->addCourseLink($course);
+                $course->addTool($courseTool);
+            }
         }
 
         return $course;
diff --git a/var/cache/.gitkeep b/var/cache/.gitkeep
old mode 100644
new mode 100755