Can I disable Dashboard in Mountain Lion?
With macOS 10.10 Yosemite or later, you can go to
System Preferences → Mission Control and switch Dashboard to Off.

                                                      

On any OS with Dashboard, you can disable it through Terminal with the following command:

defaults write com.apple.dashboard mcx-disabled -boolean YES &amp;&amp; killall Dock


It can be re-enabled with:

defaults delete com.apple.dashboard mcx-disabled &amp;&amp; killall Dock