Generally, only submissions that were uploaded since the last time the job was run will be exported. If no submissions have been uploaded since the job last ran, then no records will be found to export.
For testing purposes you may want to export the same submissions multiple times. To do this, directly select and export a range of submission from the Format tab. Set the date range of submissions to query in the top left of the screen. Click the Run button to export any submission in that range. When the export is complete the tree view on the left hand side of the screen will be refreshed with the submissions that were found in the selected range.
On occasion, you may want to re-process submissions by starting over at a specific date. To do this, set the Start At date on the Settings tab back to the date at which you want to start. You also need to click Clear Download List. During normal processing, Sync & Save tracks the submissions that have been downloaded so that it only downloads each submission once. Clearing the download list allows you to re-download submissions.
If the program is only exporting two records, then see the answer here.