I have a front end and a back end ACCESS database. The front end run daily automatically to crunch data for daily use. All the codes and processing queries and temporary tables are in the front end database, only the data holding tables are in the back end database. For some reason, probably 2 or 3 times in the month the front end database get the error 3343 - Unrecognized database format when deleting data from a linked table to the back end database. The error is generated in a simpler SQL statement such as DoCmd.RunSQL "DELETE * FROM tblMGOOverShort010Download". I started compacting both databases, but it did not help.

Any idea to resolve this problem??