Unity 3D - Game is fine in "play" but when built, player moves diagonal up+left

Question

So I just completed the first "Roll-a-ball" tutorial, but when I run the build, the game ball races to the Upper-Left corner even when I don't press any buttons.

I did the obvious stuff (reboot, build again...) but it still does it for the PC stand-alone build, and not when I play directly from Unity.

My code doesn't seem to be different from the tutorial (see link above). Here's the input handling code inside of the "PlayerController.cs":

    void FixedUpdate()
    {
        float moveHorizontal = Input.GetAxis("Horizontal");
        float moveVertical = Input.GetAxis("Vertical");

	Vector3 movement = new Vector3 (moveHorizontal, 0.0f, moveVertical);

	rb.AddForce (movement * speed);
    }

Then I added statements to print the Horizontal and Vertical. When inside the IDE and I play it, they're zero, and when I press an arrow key, they move from 0 to 1 floating point in about a second. In the built stand-alone, Horiz is -1, Vert is 1.

void SetCountText ()
{
    countText.text = 
        "Count: " + count.ToString () + "\n" + 
        "Horizontal: " + Input.GetAxis("Horizontal").ToString() + "\n" +
        "Vertical:" + Input.GetAxis("Vertical").ToString()
        ;
    if (count >= 12) {
        winText.text = "YOU WIN!!";
    }
}

Answer 1

So after a lot of digging and trying random things, I found out that it's my 3DMouse driver. Even when I didn't have the spacenavigator plugged in, there was something that Unity was seeing.

I fixed the issue in settings by unchecking all of the axis.