In the formula below if J7 is blank the result should be a blank cell, but
it is returning #N/A because the VLOOKUP is finding a blank cell when it
does it's lookup. Why is it performing the VLOOKUP and displaying #N/A when
the IF statement is False?

=IF(J70,IF(AC8=0,VLOOKUP(J7,'[Work
Shifts.xls]Sunday'!$D$2:$K$100,8,0),AC8),"")