thanks for your suggestion - please see my original point - the file was linked, then updated - the file was then re-linked, no changes made to any part of the original file, to it's location or name or anything else for that matter - and then an update was carried our which produces the error.

It does not matter how many times i re-load the original file, the error is always there on an update.

If you have a solution i would appreciate it - i have tried the file in different locations, on different drives, with a different name, but always get the same result - error.

If the original data mappinmg process works then the file itself must be set up correctly - just the link process that is faulty.