We have VBA code in an Excel workbook that assumes range names in Excel are
not case sensitive eg:
This workbook.worksheet ("Main").Range("Fimported").Value
is equivalent to:

This workbook.worksheet ("Main").Range("fimported").Value

This has been successfully deployed for many years in the Excel applications
we develop and market.

However, we have a computer with a Turkish customer where the code fails
because the code is case sensitive, but only on that computer!!

Has anyone ever experienced this and if so, what is the explanation behind
this particular computer behaving like this while every other we have
encountered is not case sensitive to range names?
Thanking you in advance.