I've created a new book, and copied the data from another wookbook
which contains new data each day.
e.g. =C:\[new_data.xls]Sheet1'!C15

After closing all the files, upon reopening my new book I get an
error, "Unable to read file". When i manually open the new_data.xls
sheet, my book then updates the data.

Can anyone suggest how or why this might be happening?

You're trying to reference a closed workbook?
Your filename\path is wrong?
Your syntax for the filename\path is wrong?

code examples help.

On 15 Jul, 14:32, Keith74 wrote:
You're trying to reference a closed workbook?
Your filename\path is wrong?
Your syntax for the filename\path is wrong?

code examples help.

Thank you,

Yes the workbook is closed. Further tests found if I open the
workbook and re-save it, the workbook in which the data is to be
imported to does not error. I suspect the application exporting the
data might be exporting an older version of excel.

I'll let you know if this is not the case.