1. Restart Lion, and before you hear the chime, hold down the Command and R keys.
2. You’ll be at the Repair Utilities screen. Click the Utilities item in the Menu Bar, then click Terminal.
3. In the Terminal window, type resetpassword and hit Return.
4. The password reset utility window launches, but you’re not going to reset the password. Instead, click on icon for your Mac’s hard drive at the top. From the dropdown below it, select the user account where you’re having issues.
5. At the bottom of the window, you’ll see an area labeled Reset Home Directory Permissions and ACLs. Click the Reset button there.
The reset process takes just a couple of minutes. When it’s done, exit the programs you’ve opened and restart your Mac.