In the menu bar of the DT3s main window the triangle with the acclamtion sign has a badge with the number 3. If I click on this icon and read - in German words - "still 3 objects to being uploaded“. Where can I see which three objects are being meant and the status of progress?
First verify your databases (see File > Verify & Repair Database…). In case of missing files check the Log panel, otherwise a toolbar search for item:pending should find the culprit.