AutoSave
AutoSave enables you to automatically save PDF files while you are working on them in the Acrobat viewer. This gives you peace of mind that your work is being saved without the worry of having to regularly save it yourself. This could save you a great deal of lost time if you were to experience a crash. You can specify the period of time that should elapse between saves. You can also decide if you just want just your front document to be saved, or all open documents that have been changed since the last Save took place.
AutoSave only starts its save when Acrobat is idle. So it won't try to do the save, for example, while you are in the middle of dragging out a link or of typing in the text for a bookmark.
AutoSave will not attempt to save temporary files or those PDFs that are being shown in another application's window, (such as a web browser).