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, for example, a printer or a console.
• 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. Compact the database and then try opening it again.