Virtual Joystick has disappeared!?!?!

Hi,

I am creating a 3D Side Scroller for mobile and was changing the settings so that the opacity would be set at zero when the menus were displayed. However now the joystick has disappeared entirely. I returned all the values to their original values and the Engine will not let me save the changes. I keep getting a message saying the asset cannot be saved - Cancel, Skip, Save.

If I reinstall the engine will I be able to open my project - I really do not want to start again from scratch. Is there an easy fix to this?

Thanks

Project Settings - Target Hardware
Set Mobile / Tablet Scaleable 3D or 2D