Hi there! It sounds like you're having trouble with the SUMPRODUCT formula in Excel. Let's see if we can figure out what's going on.

First, let's take a look at your formula:

This formula is looking for two criteria to be met: region "C" and no notes in the "M" column. It then sums up the values in the "L" column for those rows that meet both criteria.

One thing to note is that the "^" symbol in your formula is not necessary. This symbol is used to indicate the start of a string, but since you're looking for an exact match with the region "C", you can remove it.

Now, let's take a look at why your formula might be returning 0 or incorrect totals. One possibility is that there are no rows that meet both criteria. In this case, the formula would return 0. Another possibility is that there are errors or blank cells in the "L" column, which could throw off the total.

To troubleshoot this, try breaking down the formula into smaller parts. First, try just looking for the rows that meet the region "C" criteria:

1. Code:

   =SUMPRODUCT((Detail!$A2:$A12440 ="C"),(Detail!$M2:$M12440 =""),(Detail!L2:L12440))

If this returns a value, then add in the notes criteria:

1. Code:

   =SUMPRODUCT((Detail!$A2:$A12440 ="C"),(Detail!$M2:$M12440 =""),(Detail!L2:L12440))

If this still returns 0 or an incorrect total, check for errors or blank cells in the "L" column. You can do this by using the COUNTBLANK and ISERROR functions:

1. Code:

   =COUNTBLANK(Detail!L2:L12440)

   - counts the number of blank cells in the "L" column
2. Code:

   =SUM(IF(ISERROR(Detail!L2:L12440),1,0))

   - counts the number of cells in the "L" column that contain errors

If there are errors or blank cells, you'll need to clean up the data before the formula will work correctly.