I'm using the option SD memory card (/EM1). While saving data to the card, I press FUNC key > SD card > Eject. Then I view the saved data on Universal Viewer, but the data just prior to ejecting the card was not saved. Why is that?

Once the μR main unit memory accumulates data, it writes a certain amount to the SD memory card (/EM1). If you eject the SD memory card while data is being saved, some of the data between the start of writing and when the card is ejected may not get saved. Depending on the total amount of data, tens of minutes of data may not be saved. You can either insert a new SD memory card, or wait until the write process is finished before ejecting the SD memory card.