I’ve just installed Mountain Lion and wondered how the new dock would look like from a fresh installation – so had to figure out how to do that – no problem!
To completely reset the dock back to the original settings do the following:
- Delete the files com.apple.dock.plist from /Users/”user name”/Library/Preferences. Remember to replace “user name” with your OS X account name.
- Enter ‘killall Dock’ command in the terminal and press enter
rm /Users/"user name"/Library/Preferences/com.apple.dock.plist
You will find the terminal in the /Application/utilities folder or Launching Launchpad and click Terminal in the Others folder!
The tip also work on Leopard and Snow Leopard!
Please let me know if you have any comments.