There looks to be some additional folders on that SD card and these may be causing the problem. When we get this straightened out you should see a “DATA.HWR” file under the “MATRIX” folder.
Since your PC is identifying the SD card as drive “E”, go to its rot directory and right-click it and select “Format”. Be sure to uncheck “Quick Format”.
If that is an SDHC memory card and you have an old PC, then I would install Humminbird PC first and us the formatter in it so that the SDHC type memory card gets formatted correctly.