Start by booting from the Recovery HD partition. You can do this by restarting your Mac while holding down the command + r keys. Keep holding the two keys until you see the Recovery HD desktop appear.

You will see the OS X Utilities window open on your desktop, with various options available in its window. You can ignore this window; there’s nothing we need to do with it.

Instead, select Terminal from the Utilities menu at the top of the screen

In the Terminal window that opens, enter the following:

Press enter or return.

The Reset Password window will open.

Make sure the Reset Password window is the frontmost window. Then follow steps 6 through 14 in the “Reset Password – Snow Leopard (OS X 10.6) or Earlier” section to reset the user account’s permissions.

Once you quit the Reset Password app, be sure to quit the Terminal app by selecting Quit Terminal from the Terminal menu.

From the OS X Utilities menu, select Quit OS X Utilities.

You’ll be asked if you really want to exit OS X Utilities; click the Restart button.That’s all there is to resetting your user account’s file permissions back to the correct default settings. At this point, you can use your Mac as you normally would. The problems you were experiencing should be gone.