I have an item list of several thousands of items, with in column:
A - item number
B - stock balance
C - new entry
D - date
E - warehouse position

A macro adds new items to those already in stock. To make a new Balance, I do a loop through column E. If that cell is Empty (E5 for instance) I see if the item (cell A) already exists and if it does like in Cell A4, the new balance is the old balance + the new added item (B5 = C5 + B4). I then put a 'XX' in Cell E5 to make it clear that this problem has been solved. If an item is entirely new (Cell A11) then the Balance is equal to the value of cell C (B11 = C11).

Beginning of the year all goes well, but now in September the macro is slow because of the loop that looks in a few thousand of rows. I know there is a SpecialCells method but haven't managed to implement that, would that be faster and can someone show me how it should work.