I need to clarify a bit. For each day, when a start and end time is entered,
a third column in that day calculates the total hours for that day. The
final total sums all the daily hours column to get the total hours. The
final total is when I want to use the validation so that a pop up window
shows when the total sum of hours is greater than 40.

"brodiemac" wrote:

I have a spreadsheet that our different locations used for scheduling. For
each day of the week, the manager selects a start time and an end time. The
total hours then calculates in the last column using a SUM formula. What has
been requested is that an error pop up when that SUM forumula calculates
hours that are greater than 40. I've tried every variation in data
validation that I can think of but I can't get anything to work. Any
suggestions welcome. I am working in Excel 2002. Thanks!