When OSX exists out from under Oo, write locks for open files aren't cleared.

  This used to be not so much of a problem until Oo4,
   whence at least 'calc' was 'cleaned up' 
   such that no option appears to 'open anyway', ignoring the stale file lock.

   'Open anyway' sounds messier,
     but honoring the stale file lock now appears inescapable, the only option.
   
   which of course is a problem, if one has no way to clear stale file locks.

   After crashes 'RO' instances of files proliferate, with the only option to
   'copy' the 'RO' file to a completely new instance, 
    a putative increase in filesytstem 'cruft', 
    increased chance for confusing filesystem aliasing,
    and invitation for manual tedium to correct effects 
      of something which wasn't 'broken' in Oo3.

   The obvious thing to do is revert back to the old behavior,
    giving users the option of being able to override (stale) write locks. 

  no 'read only' attribute' appears on the affected files at the system level.

  a workaround may be to find where Oo keeps it's file locks, and 
  somehow remove them manually.