The location of the autosaved files can be found via the _OPTIONS-dialog (see the attached image). Via the Finder-->Go and the displayed path you can find the latest autosave-files.
1. Change the file extension via the Finder from .ds$ to .dwg
2. Open the file with the _RECOVER command to fix problems in the drawing database.
The AutoSave-Settings can be found over the Options dialog (Command _OPTIONS under Pull-down Menu Tools). Open this dialog and type AutoSave in the search line at the bottom of the dialog to open its settings.