Apple has introduced a new feature in Mac OS X Lion called Resume. Resume will automatically reopen all the windows you had open the last time you used an app after you relaunch it.
Not a bad trick for some apps, but for some others it can quickly be really annoying. Here’s a tip on how you can avoid it altogether.
Some apps like Microsoft Excel bundled in Office 2011 for Mac don’t work well with Resume and actually can generate errors or just act unexpectedly. Meanwhile other apps like Preview reopen so many previously used windows that they can be pretty annoying.
The solution is simple and you can use it whenever you don’t want Mac OS X Lion to remember the windows that were open for a particular app when you close it. All you need to do is press Command-Option-Q or press Option while selecting Quit from the apps menu bar.
Adding the Option key causes Lion to perform a Quit and Discard Windows command versus just a regular Quit command.