Starting with Lion, you’ll need to enable the User’s Library folder in order to make any changes in your User’s Library/Preferences.
Select the Finder in the Dock. Under Go in the Menu bar > hold down the Option key and you’ll see the Library.
Open the Terminal and type
chflags nohidden /Users/[username]/Library/
Return key to activate
Starting with Mavericks, Apple gave us a new option to turn on the User’s Library folder.
To toggle this option on, simply open a new Finder window and go to your home folder. Then press Command-J or choose “Show View Options” from the View menu. When done, you should see an option to “Show Library Folder” among other view options, which can be checked to reveal the Library folder.