Hi. Thanks for the replies.
The formula is on the 'New Main' sheet.
That link looks like it, Luke. I created the formula using the mouse (so clicked over onto the 'Ledger' file for the first variable, then back to the 'New Main' sheet to pick up A2. I wonder if that's what caused it...
Hello.
I've got this formula in Row 2:
=SUMIF(Ledger!$E$4:$E$1333,'New Main'!A2,Ledger!$AP$4:$AP$1333)
I always build up and check my row formulae first, then simply copy them down to the last row on the sheet. At some point I sorted the spreadsheet, and somehow although many rows had the...