diff --git a/gns3server/compute/vmware/__init__.py b/gns3server/compute/vmware/__init__.py
index 9fda4c50..7bcea043 100644
--- a/gns3server/compute/vmware/__init__.py
+++ b/gns3server/compute/vmware/__init__.py
@@ -107,7 +107,7 @@ class VMware(BaseManager):
             else:
                 vmrun_path = "vmrun"
 
-        if not os.path.isabs(vmrun_path):
+        if vmrun_path and not os.path.isabs(vmrun_path):
             vmrun_path = shutil.which(vmrun_path)
 
         if not vmrun_path: