By default IE is programmed to reopen in the state in which it was closed. Meaning if in your previous session is was closed in a restore state it will open in the smaller window on your desk top. The key is to make sure it is fully maximized before closing your session. What can make it behave erratically is when you get pop up windows that are in a restore state and you close them last ... your browser will reopen in the smaller state ... I know it is frustrating but I do not know of any way you can change this behavior.