- A number in a cell is too wide for the cell to display it.
 - The formula in the cell produces a result that is too wide for the cell.
 - There is a negative number in the cell that has been formatted for dates or times. Dates and times in Excel must be positive values.
 
- Widen the column containing the problem cell.
 - Change the format of the problem cell to something other than a date/time format.
 - Correct the negative number in a date/time formatted cell.