If you are importing data into Excel or using an excel datasheet as a data source in, for example, an MS Query you can observe unexpected results as Excel tries to be cleverer than it is.

Only the first eight rows of your data are scanned to determine the datatype for the column, i.e. is it a number or is it text. If you have a data column which uses both, but, say only text appears in the first eight rows, the number values will not be displayed. You will be left with blanks instead of the values.

The workaround is that you have to explicitly define each of your data columns before you import your data. Do this before you import your data to avoid having to F2 through the fields (another datatype weakness in Excel !)

This is partly explained in Microsoft article KB141284 or Q141284