If you add or delete columns from the database source of an existing and ready to use fuzzy index that has automatic update configured, remember to change the import settings before the automatic update is performed. Otherwise the update reimports the fuzzy database, and records that do not have the same number of configured columns are not imported; therefore you end up with a fuzzy database that contains no records. Though the server logging report for the update stores the information about the number of imported and not imported records, the import is successfully completed and the database status is still set to Ready. Any search requests for such a database do not return any results.

By default, if an automatic update of a fuzzy index fails, searches can still be performed as the system does not switch to the updated fuzzy index, but continues to use the previous version. For example, if the database source was temporarily unavailable because virus detection locked the file. You can change this behavior by selecting the Error Management option. Then, if the automatic update fails the database status of the fuzzy database is changed to Error. A fuzzy database that has this database status cannot perform any search requests and it does not change the status until it is successfully imported again. You have to either check the import settings and import the database again, or wait for the next successful update.