Does the existing workbook use other separators? Look at the formulas, maybe a semicolon is used instead of a comma.
You can use ToolsOptionsInternational tab to change the settings.

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Kind regards,

Niek Otten
Microsoft MVP - Excel

"ajd" wrote in message ...
|I am trying to join a text string and a number into another text string.
| When I open a new excel document and type in =CONCATENATE("t",3) for example,
| it properly returns "t3". I have an existing workbook though which has
| numerous spreadsheets and equations, etc already setup, for which I type the
| same formula in a blank cell and it returns the #VALUE error. The format on
| the cell is General and everything seems to be the same between the existing
| workbook and the new workbook, but the equations respond differently. Does
| anyone know what is causing this #VALUE error, and what I can do to fix it in
| the existing sheet? Thanks.