For some reason the email address is invalid, so I'm re-posting here.

That's the danger with a shared workbook. If this is your workbook that you
share with others, then I suggest that you make it Read-Only. Others would
need to save it to their pc, make changes to their copy and submit it back
to you to update the master shared workbook. I know it won't be real time
sharing and will entail more work on your end, but which is worse?

Mike F