Just a guess at a workaround.

Add an
application.calculate
line in the open event of that workbook to see if forcing a recalc helps.

Victor wrote:

I have a function in an addin i created which does some basic calculations
which is loaded and saved however when i open a spreadsheet that was saved
with calls to this function I get the #Name error

the addin is loaded when I open excel because if i add any more of these
functions into the spreadsheet it works, on loading the spreadsheet Excel
seems to process the sheet before loading the addins so fails

I works fine on some computers but not on others

--

Dave Peterson