Excel 2007 sharing workbooks

[Michelle]

We want to be able to share an Excel workbook with users on a network drive.
We want the Excel workbook to update automatically when edits are made,
without having to save. I understand that Excel can do this.

I have selected Shared Workbook > Advanced tab > Update Changes >
Automatically every 5 minutes > Save my changes and see others' changes.
But it's not happening.

Does anyone have any ideas?

Thanks,