If you encounter a failed Archicad autosave (Crash followed by no recovery dialog at relaunch), and you are running Time Machine in OS X, restore the Autosave folder from Time Machine instead of messing with cron job workarounds.
Make sure Archicad is not running.
Activate Time Machine on the Dock.
Navigate to [Home]/Library/Application Support/Graphisoft/. You should see a folder called Archicad Autosave Folder. If you don't, go 'back in time' by clicking the next window. If you see more than one Autosave folder, sort the window by Date Modified to determine the right one.
Highlight that folder and click the Restore button. (You shouldn't get a 'replace this folder' warning, because if the Archicad Autosave Folder was present, Archicad would have seen it and given you the recovery dialog. If you do get it, make sure Archicad is not running.)
Once the folder copies over, relaunch Archicad. It should find the Autosave data and present you with the recovery dialog. Depending on when Time Machine ran last, you may have lost more work than you would with a normal autosave.