Unrecognized database format <filename>. (Error 3343)

Possible causes:

• The specified file name is not a Microsoft Jet database.
  
  
• The specified file name is a device name, such as a printer, a console, and so forth.
  
  
• The .mdb file has invalid header information or an unknown sort order.
  
  
• A commit is pending from another user, but the lock file cannot be found.
  
  
• During a commit, you are attempting to write a Long value larger than the 2K maximum page size.
  
  
• The database is damaged. Repair and compact the database, and then try opening it again.