This may be resolved by either of the following two solutions:

Ensure that report Select Distinct record values only

  1. Go to File, Report Options
  2. Mark the checkbox for the setting Select Distinct Data for Browsing
  3. Click OK
Change the 500 limit in the Registry Key
  1. In Windows, click on Start, Run and enter Regedit
  2. Go to HKEY_CURRENT_USER,Software, Business Objects, Suite 11.0, Crystal Reports, DatabaseServer, MaxNBrowseValues* (Crystal Reports XI R1)  - OR - 
  3. Go to HKEY_CURRENT_USER, Software, Seagate Software, Crystal Reports, Database Server, MaxNBrowseValues * (Crystal Reports 8.5)
  4. Right click this key and select Modify (Base=Decimal), and change the value from the default of 500 to a higher value
* If MaxNBrowseValues does not exist then create it (right click DatabaseServer, New, DWORD Value, enter MaxNBrowseValues).