This is message we receive from users quite often, indicating they can only view "part" of the records in the data file. Our delivery system only tracks download after a complete/successful download has occurred. Further, if only "part" of the data was downloaded, it would be a corrupted file, and could not be opened at all.
Inevitably, this is almost always a user that is downloading the CSV version of the data, and then trying to open it in Microsoft Excel. Further, it is users using a MS Excel 2003 or earlier as well.
Excel 2003 and prior has native row limitations of 65,536 rows by 256 columns
If you have Excel 2013 or higher your limitations are about 1,048,576 rows by 16,384 columns
If you "Must" work with the data inside of Excel, and do not have a newer version to display more/all of the data, you will need to split your file up into smaller ones. You can do this manually, by opening the CSV inside of a standard text editor, and carving it up.
Or, alternatively you can use a file splitter tool to do the job for you. We have even linked to a free one from within your client account area called Text File Cleaver (top right sidebar in your control panel).
For convenience, A link to this application is here as well