Here is the whole formula:

=IF(AND(($X2+$Y2)=MAX(($X2+$Y2),($AF2+$AG2),($AN2+ $AO2),($AT2+$AU2),($AZ2+$BA2),($BF2+$BG2)),($X2+$Y 2)=BQ$2),$V6,IF(AND(($AF2+$AG2)=MAX(($X2+$Y2),($A F2+$AG2),($AN2+$AO2),($AT2+$AU2),($AZ2+$BA2),($BF2 +$BG2)),($AF2+$AG2)=BQ$2),$AD6,IF(AND(($AN2+$AO2) =MAX(($X2+$Y2),($AF2+$AG2),($AN2+$AO2),($AT2+$AU2) ,($AZ2+$BA2),($BF2+$BG2)),($AN2+$AO2)=BQ$2),$AL6, IF(AND(($AT2+$AU2)=MAX(($X2+$Y2),($AF2+$AG2),($AN2 +$AO2),($AT2+$AU2),($AZ2+$BA2),($BF2+$BG2)),($AT2+ $AU2)=BQ$2),$AR6,IF(AND(($AZ2+$BA2)=MAX(($X2+$Y2) ,($AF2+$AG2),($AN2+$AO2),($AT2+$AU2),($AZ2+$BA2),( $BF2+$BG2)),($AZ2+$BA2)=BQ$2),$AX6,IF(AND(($BF2+$ BG2)=MAX(($X2+$Y2),($AF2+$AG2),($AN2+$AO2),($AT2+$ AU2),($AZ2+$BA2),($BF2+$BG2)),($BF2+$BG2)=BQ$2),$ BD6,"--"))))))

"Harlan Grove" wrote:

manxman wrote...
At the start of this formula, I want to add a 7th IF statement that checks
the condition of another cell, and sets this whole formula to "--" if the
other cell is "". When I try to add it, I get a standard formula error
message box, and then the last MAX is highlighted. What's going on?

=IF((AND((X2+Y2)=MAX((X2+Y2),(AF2+AG2),(AN2+AO2), (AT2+AU2),(AZ2+BA2),
(BF2+BG2)),(X2+Y2)=BQ2),V6,IF
{and so on five more times, checking next AF+AG. The formula ends with: if false, "--".
(I have left out the $ before each cell reference for brevity.
The entire formula is about 700 to 900 characters long, depending how far
down the sheet it is, but I can't add the 7th IF statement to even the
shortest one.)
....

Don't worry about brevity. Post your entire actual working formulas as
plain text. If you mean you're checking whether each of the X+Y, AF+AG,
AN+AO, etc. values equals the maximum of all such values, you don't
need multiple IFs. You could use a lookup.

=INDEX(V6*{1;0;0;0;0;0}+AL6*{0;1;0;0;0;0}+...,MATC H(MAX(X2+Y2,AF2+AG2,...),
(X2+Y2)*{1;0;0;0;0;0}+(AF2+AG2)*{0;1;0;0;0;0}+..., 0))

which can easily be modified to

=IF(A1="","--",INDEX(...))

that without the underlying data cells being filled in, a #VALUE! error is
reported. Cells X,Y,AF,AG, etc. are themselves formulas, and are set to
equal "" when the underlying data are absent. . . .
....

If these cells could be "", then using them as arithmetic operands will
generate #VALUE! errors. If they should be treated as zeros, why not
set them to 0 rather than ""? Alternatively, wrap them inside N()
calls, e.g.,

=IF(A1="","--",INDEX(N(V6)*{1;0;0;0;0;0}+N(AL6)*{0;1;0;0;0;0}+. ..,
MATCH(MAX(N(X2)+N(Y2),N(AF2)+N(AG2),...),(N(X2)+N( Y2))*{1;0;0;0;0;0}
+(N(AF2)+N(AG2))*{0;1;0;0;0;0}+...,0))