Macro randomly misses out on a cell.

Workbook Event code should be added to the workbook code module:

Copy the Excel VBA code that you want to use
Select the workbook in which you want to store the code
Hold the Alt key, and press the F11 key, to open the Visual Basic Editor
In the Project Explorer, find your workbook, and open the list of Microsoft Excel Objects
Right-click on the ThisWorkbook object, and choose View Code
Where the cursor is flashing, choose Edit | PasteTo best describe or illustrate your problem you would be better off attaching a dummy workbook. The workbook should contain the same structure and some dummy data of the same type as the type you have in your real workbook - so, if a cell contains numbers & letters in this format abc-123 then that should be reflected in the dummy workbook.

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Hello.

Ok I made a sample file as you asked and will upload it.
The run button on the top will run the macro in question. It will spit out a new worksheet starting with "BID" followed by 4 random numbers. In that worksheet you want to look at column "H" and it should sum to 0. However in this case it doesn't. It seems like the macro works fine but it misses out on a cell in the original worksheet. The cell in question is "I1174". In the BID sheet, the debit column values should be positive and credit should be negative and should all be in the same column. It missed out on that cell when copying the credit column values, but copied everything else before and after it.