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harold_dolman 

This problem can occur for several reasons, so we need more details to understand enough about YOUR specific situation to offer suggestions.

Does this happen with any query, or with just one?

Are you trying to join a number of tables into a single query? Or is this a query on a single table?

What parameters, if any, are applied to the query? 

Are you using any VBA functions in the query?

Are appropriate fields in the table(s) to which the query is bound indexed? 

Are you specifying joins between tables -- if multiple tables are involved?

How many records are in the table(s)? 

Are you working with tables linked from a remote server like SQL Server? Or another accdb? Or within a single accdb?

Thanks for providing sufficient background to address potential issues.