Tool-bar error message in Emacs: "better pass an explicit argument"

Question

I have this message at every startup of Emacs :

Toggling tool-bar-mode off; better pass an explicit argument.

It is related to this line of code in my .emacs :

(tool-bar-mode nil)

I see nothing wrong in my code. How can I fix this message?

Answer 1

nil is the lack of a value. The message is telling you to use an actual value.

Use (tool-bar-mode -1) instead.