Backing up your database
We’ve made OmniFocus err on the side of obsessive, paranoid data preservation, just in case something bad happens to your database. After all, we’re asking you to put your whole life into this app.
OmniFocus automatically backs up your database once a day, in the folder ~/Documents/OmniFocus Backups/. To change when the automatic backups happen, or where they are saved, choose Preferences from the OmniFocus menu and use the General pane. You can choose to back up once or twice a day, and also to back up whenever you quit OmniFocus.
To manually back up your database, choose Back Up Database from the File menu. You can choose where to put the backup.
To restore a backed-up version of your database, choose Revert to Database Backup from the File menu, then choose a backup file to use. Your entire database is replaced by the version in the file; if you’re not sure that the backup is what you want, you can double-click the backup file in Finder to open it in its own window first and make sure it’s right.