It sounds as if you have something in the Report->Selection Formulas->Record which is limiting the rows returned.
Please post technical information, saying that you use a parameter isn't descriptive.
Parameters are NOT dynamic in Crystal, they will NOT refresh with the latest values from their source, and parameters are limited to X values within the table depending upon the values in the MaxNBrowseValues and BrowseTimeout in the Registry, which I believe is 500 in 8.5.
So state how you are using the parameter (not just that you do), where you are displaying the field, and someone can help you.
If you drop the table.field (not the parameter) in the details section of the report, it won't be limited unless you filter the rows in the record selection, or you use suppression in the section you're displaying in.
-k
-k