User can't receive mail due to C00E error

All mail sent to one user gets returned with a C00E error message: Invalid Index Number.

 

A structure check on the user's database reports an error, but does not fix it:

      Verifying data
          Error 22- Database check error: BAD_IX (0xC00E)
          Suggestion- Database file missing or invalid.
          No direct recovery possible.  Attempt to recover file from external backup.
          If no backup exists, request explicit structural rebuild from Admin and the
          database will be removed from Guardian database, to allow re-create.
          However, all data previously contained in the database will be lost!

 

22 Miscellaneous check errors in database check.......     1

 

This is a problem with the user's index file. To fix recreate the index file, run a structural rebuild on the user from gwcheck.

 

The documentation on running a structural rebuild can be found here.