diff --git a/binarycpython/utils/grid.py b/binarycpython/utils/grid.py
index 04fb95085ac546687bb0316310502fb7028bcfb2..56de13f4f7f2d74d4257c9473ec80ecfe1ed1b93 100644
--- a/binarycpython/utils/grid.py
+++ b/binarycpython/utils/grid.py
@@ -1116,7 +1116,7 @@ class Population:
         for dir in dirs:
             path = self.grid_options[dir]
             if path != None and dir_ok(path) == False:
-                print("Directory",dir,", currently set to",path,", cannot be written to. Please check that this directory is correct and you have write access.")
+                print("Directory {dir} currently set to {path} cannot be written to. Please check that this directory is correct and you have write access.".format(dir=dir,path=path))
                 sys.exit(1)
 
         return