Apple Logic Express 9 - Manual (Page 181)

You can define the number of project backups you want to keep by changing the Auto
Backup setting in the Logic Express > Preferences > General > Project Handling pane.
Your choices are:
• Off
• Last Project Version
• Last 3 Project Versions
• Last 5 Project Versions
• Last 10 Project Versions
• Last 30 Project Versions
• Last 50 Project Versions
• Last 100 Project Versions
Reverting to the Saved Version
Any time you make a mistake, you can undo it by choosing Edit > Undo (or use the
corresponding key command, default assignment: Command-Z).
If you have made some really serious blunders (as unlikely as that may be), or you decide
that in the 15 minutes since you last saved, your creative efforts have resulted in material
too unpleasant to describe politely, you may find the File > Revert to Saved function (or
the corresponding key command) very helpful. This replaces the current project with the
previously saved version.
181 Chapter 7 Working with Projects