This article was previously published under Q257408
This article has been archived. It is offered "as is" and will no longer be updated.
This article applies only to a Microsoft Access database (.mdb).
Novice: Requires knowledge of the user interface on single-user computers.
For a Microsoft Access 2002 version of this article, see 291162.
After you compact and after you repair a database that includes a table that has an AutoNumber field, you notice that when you enter new data, the AutoNumber is a duplicate of an earlier AutoNumber.
This problem has been fixed in the latest edition of the Jet Service Pack. For additional information about how to obtain the latest version of the Jet 4.0 database engine, click the following article number to view the article in the Microsoft Knowledge Base:
239114 How To: Obtain the Latest Service Pack for the Microsoft Jet 4.0 Database Engine
Microsoft has confirmed this to be a problem in Microsoft Jet version 4.0.2927.4 and earlier.
When you use an AutoNumber field to generate counter values, a duplicate value may be generated.