Excel's Error Checking to Your Needs
Anyone with any experience building Excel worksheets knows that formula errors, the bane of all spreadsheets, are inevitable. Whenever Excel cannot successfully calculate one of your formulas according to its internal rules, the program returns an error value to its cell, indicated by the error name in all caps punctuated by a number sign at the beginning (#) and an exclamation point (!) or question mark (?) at the end, as in #VALUE!, #NAME?, and #DIV/0!, to name but a few.
Not only are these error values ugly as sin, but they also tend to propagate themselves all over the worksheet, spreading to all formulas that refer to the cells that contain them.
In an attempt to help you identify what in the blazes has caused your formula to go haywire and return an error value rather than the result you wanted, Excel now adds error indicators to cells. These indicators appear as tiny green triangles in the upper-left corner of the cells containing the error values. When you position the mouse pointer over an error indicator, a Smart Tab icon (the exclamation point in a diamond) appears with a ToolTip containing an explanation of the problem.
When you're new to Excel, the ToolTips connected to the error indicators are a godsend because they reinforce the rules and start to make sense of those largely inexplicable error values. As you become a more experienced user, they lose their luster and can become downright annoying (obscuring data you want to see and otherwise getting in your way as you inadvertently pass the mouse pointer over them).
Fortunately, Excel makes it easy to control when error indicators appear in cells containing error values. You can also temporarily suppress the display of all error indicators in the worksheet. As part of this technique on cleaning up the error indicators in your worksheet, I give you tips on temporarily suppressing the display of those unsightly error values both on-screen and in your printouts.