Subform not gathering all records from Main Form

[compstudent]

I am having issues with my subform loading all records from the main table that its linked with. My main table has 8,849 records that fall Group 1 but only 8,831 records are showing up in my subform. I need to figure out how I can fix this. By a SQL code or VB code. Would really appreciate the help. Thank you!

[June7]

Why should there be the same number of records? Are these two tables having 1-to-1 relationship? Apparently 18 records don't have correct key. If this is 1-to-1 relationship, possibly some group(s) has too many records. Do a query that calcs a count of records for each group in both tables. Which ones are not in agreement?