Excel files are in a propriertary microsoft format. A LabVIEW "spreadsheet" file is a file containing an ASCII table with tabs separating columns and linefeeds separating rows. They are not ther same! 🙂
If you use "write to spreadsheet file" and name the file *.xls, this does NOT make it an excel file, it just tells the operating system to open it with excel if you double-click it. Excel is smart enough to notice that it is not really an excel file and does its best to convert it transparently. The same does not work in reverse.
You have several options:
- You can use excel to export your data to something LabVIEW can read. Try e.g. tab delimited text.
- You can use e.g. activeX to read an excel file, see: http://zone.ni.com/devzone/cda/epd/p/id/3409
- Search for excel in your example finder for more possibilites.