MESTRELLA29 wrote:
=SUMPRODUCT(--(GDOS!$C$3:$C$10000=$C3),GDOS!$B$3:$B$10000)

This formula is trying to work as a VLOOKUP for text "1C"

Right now the result of this formula is 0, does anyone know why and how can
I correct this?

Thanks

Two possibilities...

(1) Cells in C might have extraneous (non-printable) chars around the
entries (which you can remove with the TrimAll macro whose code you can
track down with Google).

(2) Numbers in B are not true numbers. To force them into true numbers:
Copy an unused, empty cell. Select the range in B. Run Edit|Paste
Special with the Add option checked.

Finally, you have a single condition, that is, the range in C on GDOS
must be equal to C3. In such cases, the right thing to do is to invoke a
formula with SumIf...

=SUMIF(GDOS!$C$3:$C$10000,$C3,GDOS!$B$3:$B$10000)

which is an efficient (i.e., fast).