When you launch an application, it appears exactly as you left it. All the open windows, palettes, and panes — even the cursor position and highlighted text — come back just as they were.
This feature is great for some but very bothersome for others. If you want a clean slate each time you reopen an application the instructions below will show you how to disable Resume.
Click to select System Preferences… from the Apple menu at the top left of your screen.
Select General from the Personal section of System Preferences.
Uncheck the box labeled Restore windows when quitting and re-opening apps.