If the external source is not going to be open, you must include the path to
the file location:

=SUM('C:\Reports\[Budget.xlsx]Annual'!C10:C25)

If on a network drive, use the UNC path instead of a named drive.

=SUM('\\servername\sharename\folders(s)\[Budget.xlsx]Annual'!C10:C25)

"Virpi H" wrote:

Hi,
I'm gathering information to a seperate Total workbook from several
different woorksbooks (weekly files which has always the same format). On
Total woorkbook I'm having formula like =SUMIF([w28_08.xls]report!$G:$G,
"July", [w28_08.xls]report!$I:$I) and it works fine when the W28_08 document
is open, but when it closed and and I update the information when opening the
destination file(Total) it just gives me #Value! to all the cells which have
the formula.
Any kind of help would be appricated.

--
Thanks in advance, Virpi