Comparing Two Large Tables in Microsoft Access 97

I have two tables that both have a field that represents a unique ID. Field 1 of the first table and Field 14 of the second table. Ultimately, I was trying to get a list from the Eligible table that didn't exist in the "Enrolled" table. What am I doing wrong?

I created the report in design view, then I modified the SQL as below.

The result is that my program is freezing up. I'm using Microsoft Access 97. I don't know if my query works or if it's just too slow that I will never see the query run as both tables are 20,000 to 30,000 records. Any ideas would help!Start Free Trial

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SELECT Eligible.Field14
FROM Eligible
WHERE Eligible.Field14 NOT IN
   (SELECT Enrolled.Field1
    FROM Enrolled);