HT Integrate copies of shared workbook automatically

[Katie]

I work at a help desk, and I have a caller who has a shared workbook.

He emails copies of that workbook to others, who make changes, and email the
copies back. He says when he opens the copies, they used to automatically
prompt him to update the master.

They don't prompt anymore, and he doesn't remember setting itup, but wants
that feature back.

Does anyone know how to set up a shared workbook so that when copies are
opened, they prompt to update the master?

Thanks.