To adjust permissions:

Open your hard disk, open the Users folder, and then open your home folder (the one named after you).

Click the Library folder to select it, and then choose File > Get Info to open the Library Info window.

Click the arrow next to “Sharing & Permissions” to expand this section.
On earlier versions of Mac OS X, the section is labeled “Ownership & Permissions.”

Choose Read & Write from the pop-up menu next to your user name. You may need to click the lock icon and supply your password.
On earlier versions of Mac OS X, the pop-up menu appears next to the words “You can.”

Open the Action (gear) menu and choose “Apply to enclosed items.” Click OK when a prompt asks if you’re sure.
On earlier versions of Mac OS X, click the “Apply to enclosed items” button.

Click the lock icon again to prevent further changes.