#MISSING in a cell indicates the cell contains no data, whereas zero in a cell is a data value. #MISSING decreases the database size and improves performance.
You can replace #MISSING by selecting the cell and typing a value. You can also replace irrelevant data in a cell and save the cell as #MISSING, which writes #MISSING to the database.
To write #MISSING to cells:
You can select a range of contiguous cells by clicking in the upper-left cell in the range, and pressing Shift + click to select the lower-right cell in the range. You can select rows and columns by clicking row and column headings. Select a range of rows or columns by using Shift + click.
If the designer sets a data form to suppress missing data, and an entire row contains #MISSING (no data), that row does not display on the data form.
You can also enter #MISSING using Smart Lists. See Entering Data with Smart Lists.
The cells are set to #MISSING when you save the data form.