The autosave vault for FCP X is not in that location. Assuming your projects and events were on the external drive, The backup is in:
[External drive] -> Final Cut Projects -> [Project Name] -> Backups
[ ] indicate variables, e.g. drive name, project name. The event backup is along a similar path but Final Cut Events.
Before you try that though download Digital Rebeillion’s pref manager and trash the prefs in case anything is wrong there.
Also – is the external drive mounting OK? Can you see the Final Cut Event and Project folders in the root dir of the drive?
Good luck!
Michael Sanders
London Based DP/Editor