The task will be now completed.

The index will be recreated.

The database can't be read.  Use a backup.

The database has probably been damaged.  Restore the database from a backup.

Use 4D Tools to repair the database.

 while deleting a record from the file: 

 while deleting an index. 

 while creating an index. 

 while saving the internal directory. 

There was an interruption